Mesomorphic compound, liquid crystal composition containing the compound, liquid crystal device using the composition, liquid crystal apparatus and display method

ABSTRACT

A mesomorphic compound of the formula (I) according to Claim 1 characterized by having at least two ether groups between alkylene groups in a specific alkoxy perfluoroalkyl terminal group is suitable as a component for a liquid crystal composition providing improved response characteristics and a high contrast. A liquid crystal device is constituted by disposing the liquid crystal composition between a pair of substrates. The liquid crystal device is used as a display panel constituting a liquid crystal apparatus providing good display characteristics.

This application is a continuation of application Ser. No. 08/300,527,filed Sep. 6, 1994, now abandoned.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a mesomorphic compound, a liquidcrystal composition, a liquid crystal device, a display apparatus and adisplay method, and more particularly to a mesomorphic compound, aliquid crystal composition containing the compound with improvedresponsiveness to an electric field, a liquid crystal device using thecomposition for use in a display device, a liquid crystal-opticalshutter, etc., a liquid crystal apparatus using the device particularlyas a display device, and a display method of using the composition.

Hitherto, liquid crystal devices have been used as an electro-opticaldevice in various fields. Most liquid crystal devices which have beenput into practice use TN (twisted nematic) type liquid crystals, asshown in "Voltage-Dependent Optical Activity of a Twisted Nematic LiquidCrystal" by M. Schadt and W. Helfrich "Applied Physics Letters" Vol. 18,No. 4 (Feb. 15, 1971) pp. 127-128.

These devices are based on the dielectric alignment effect of a liquidcrystal and utilize an effect that the average molecular axis directionis directed to a specific direction in response to an applied electricfield because of the dielectric anisotropy of liquid crystal molecules.It is said that the limit of response speed is on the order of μsec,which is too slow for many uses. On the other hand, a simple matrixsystem of driving is most promising for application to a large-area flatdisplay in view of cost, productivity, etc., in combination. In thesimple matrix system, an electrode arrangement wherein scanningelectrodes and signal electrodes are arranged in a matrix, and fordriving, a multiplex driving scheme is adopted wherein an address signalis sequentially, periodically and selectively applied to the scanningelectrodes and prescribed data signals are selectively applied inparallel to the signal electrodes in synchronism with the addresssignal.

When the above-mentioned TN-type liquid crystal is used in a device ofsuch a driving system, a certain electric field is applied to regionswhere a scanning electrode is selected and signal electrodes are notselected (or regions where a scanning electrode is not selected and asignal electrode is selected), which regions are called "half-selectedpoints". If the difference between a voltage applied to the selectedpoints and a voltage applied to the half-selected points is sufficientlylarge, and a voltage threshold level required for allowing liquidcrystal molecules to be aligned or oriented perpendicular to an electricfield is set to a value therebetween, display devices normally operate.However, in fact, as the number (N) of scanning lines increases, a time(duty ratio) during which an effective electric field is applied to oneselected point when a whole image area (corresponding to one frame) isscanned decreases with a ratio of 1/N. Accordingly, the larger thenumber of scanning lines are, the smaller is the voltage difference ofan effective value applied to a selected point and non-selected pointswhen scanning is repeatedly effected. This leads to unavoidabledrawbacks of lowering of image contrast or occurrence of interference orcrosstalk. These phenomena are regarded as essentially unavoidableproblems appearing when a liquid crystal having no bistability (i.e.liquid crystal molecules are horizontally oriented with respect to theelectrode surface as stable state and is vertically oriented withrespect to the electrode surface only when an electric field iseffectively applied) is driven (i.e. repeatedly scanned) by making useof a time storage effect. To overcome these drawbacks, the voltageaveraging method, the two-frequency driving method, the multiple matrixmethod, etc. have been already proposed. However, any method is notsufficient to overcome the above-mentioned drawbacks. As a result, thedevelopment of large image area or high packaging density in respect todisplay elements is delayed because it is difficult to sufficientlyincrease the number of scanning lines.

To overcome drawbacks with such prior art liquid crystal devices, theuse of liquid crystal devices having bistability has been proposed byClark and Lagerwall (e.g. Japanese Laid-Open Patent Appln. No.56-107216; U.S. Pat. No. 4,367,924, etc.). In this instance, as theliquid crystals having bistability, ferroelectric liquid crystals havingchiral smectic C-phase (SmC*) or H-phase (SmH*) are generally used.These liquid crystals have bistable states of first and second stablestates with respect to an electric field applied thereto. Accordingly,as different from optical modulation devices in which theabove-mentioned TN-type liquid crystals are used, the bistable liquidcrystal molecules are oriented to first and second optically stablestates with respect to one and the other electric field vectors,respectively. Further, this type of liquid crystal has a property(bistability) of assuming either one of the two stable states inresponse to an applied electric and retaining the resultant state in theabsence of an electric field.

In addition to the above-described characteristic of showingbistability, such a ferroelectric liquid crystal (hereinafter sometimesabbreviated as "FLC") has an excellent property, i.e., a high-speedresponsiveness. This is because the spontaneous polarization of theferroelectric liquid crystal and an applied electric field directlyinteract with each other to induce transition of orientation states. Theresultant response speed is faster than the response speed due to theinteraction between dielectric anisotropy and an electric field by 3 to4 digits.

Thus, a ferroelectric liquid crystal potentially has very excellentcharacteristics, and by making use of these properties, it is possibleto provide essential improvements to many of the above-mentionedproblems with the conventional TN-type devices. Particularly, theapplication to a high-speed optical shutter and a display of a highdensity and a large picture is expected. For this reason, there has beenmade extensive research with respect to liquid crystal materials showingferroelectricity. However, previous ferroelectric liquid crystalmaterials do not sufficiently satisfy characteristics required for aliquid crystal device including low-temperature operationcharacteristic, high-speed responsiveness, high contrast, etc.

More specifically, among a response time τ, the magnitude of spontaneouspolarization Ps and viscosity η, the following relationship (II) exists:τ=η/(Ps·E) . . . (II), where E is an applied voltage. Accordingly, ahigh response speed can be obtained by (a) increasing the spontaneouspolarization Ps, (b) lowering the viscosity η, or (c) increasing theapplied voltage E. However, the driving voltage has a certain upperlimit in view of driving with IC, etc., and should desirably be as lowas possible. Accordingly, it is actually necessary to lower theviscosity or increase the spontaneous polarization.

A ferroelectric chiral smectic liquid crystal having a large spontaneouspolarization generally provides a large internal electric field in acell given by the spontaneous polarization and is liable to pose manyconstraints on the device construction giving bistability. Further, anexcessively large spontaneous polarization is liable to accompany anincrease in viscosity, so that remarkable increase in response speed maynot be attained as a result.

Moreover, if it is assumed that the operation temperature of an actualdisplay device is 5°-40° C., the response speed changes by a factor ofabout 20, so that it actually exceeds the range controllable by drivingvoltage and frequency.

In general, in a liquid crystal device utilizing birefringence of aliquid crystal, the transmittance under right angle cross nicols isgiven by the following equation:

    I/I.sub.0 =sin.sup.2 4θ·sin.sup.2 (Δnd/λ)π,

wherein I₀ : incident light intensity,

I: transmitted light intensity,

θ: tilt angle,

Δn: refractive index anisotropy,

d: thickness of the liquid crystal layer,

λ: wavelength of the incident light. Tilt angle θ in a ferroelectricliquid crystal with non-helical structure is recognized as a half of anangle between the average molecular axis directions of liquid crystalmolecules in a twisted alignment in a first orientation state and asecond orientation state. According to the above equation, it is shownthat a tilt angle θ of 22.5 degrees provides a maximum transmittance andthe tilt angle θ in a non-helical structure for realizing bistabilityshould desirably be as close as possible to 22.5 degrees in order toprovide a high transmittance and a high contrast.

However, when a birefringence of a liquid crystal is utilized in aliquid crystal device using a ferroelectric liquid crystal in anon-helical structure exhibiting bistability reported by Clark andLagerwall, the following problems are encountered, thus leading to adecrease in contrast.

First, a tile angle θ in a ferroelectric liquid crystal with anon-helical structure obtained by alignment with a polyimide filmtreated by rubbing of the prior art has become smaller as compared witha tilt angle H (the angle H is a half of the apex angle of the coneshown in FIG. 4 as described below) in the ferroelectric liquid crystalhaving a helical structure, thus resulting in a lower transmittance.

Secondly, even if the device provides a high contrast in a static state,i.e., under no electric field application, liquid crystal moleculesfluctuate due to a slight electric field at a non-selection period oftime in a matrix drive scheme in the case of applying a voltage to theliquid crystal molecules for providing a display image, thus resultingin the display image including a light (or pale) black display state,i.e., a decrease in a contrast.

Thus, as described hereinabove, commercialization of a ferroelectricliquid crystal device requires a liquid crystal composition assuming achiral smectic phase which provides a high contrast, a high-speedresponsiveness and a small temperature-dependence of response speed.

In order to afford uniform switching characteristics at display, a goodview-angle characteristic, a good storage stability at a lowtemperature, a decrease in a load to a driving IC (integrated circuit),etc. to the above-mentioned ferroelectric liquid crystal device or adisplay apparatus including the ferroelectric liquid crystal device, theabove-mentioned liquid crystal composition is required to optimize itsproperties such as spontaneous polarization, an chiral smectic C (SmC*)pitch, a cholesteric (Ch) pitch, a temperature range showing amesomorphic phase, optical anisotropy, a tilt angle and dielectricanisotropy.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a mesomorphic compoundproviding a high speed responsiveness, a high contrast and a decreasedtemperature-dependence of response speed; a liquid crystal composition,particularly a chiral smectic liquid crystal composition containing themesomorphic compound for providing a practical ferroelectric liquidcrystal device as described above; a liquid crystal device including theliquid crystal composition and affording good display performances; aliquid crystal apparatus including the device; and a display methodusing the composition.

According to the present invention, there is provided a mesomorphiccompound represented by the following formula (I):

    C.sub.m F.sub.2m+1 (CH.sub.2).sub.n O(CH.sub.2).sub.p O(CH.sub.2).sub.q--Y.sub.1, --A.sub.1 --R.sub.1           (I),

wherein R₁ denotes H, halogen, CN, or a linear, branched or cyclizedalkyl group having 1-30 carbon atoms capable of including at least one--CH₂ -- group which can be replaced with --O--, --S--, --CO--,--CH(Cl)--, --CH(CN)--, --CCH₃ (CN)--, --CH═CH-- or --C.tbd.C-- providedthat heteroatoms are not adjacent to each other and capable of includingat least one H which can be replaced with F;

m, n, p and q independently denote an integer of 1-15 provided thatm+n+p+q≦18;

Y₁ denotes a single bond, --O--, --CO--, --COO--, --OCO--, --CH═CH-- or--C.tbd.C--; and

A₁ denotes --A₂ --, --A₂ --X₁ --A₃ -- or --A₂ --X₁ --A₃ --X₂ -- A₄ inwhich

A₂, A₃ and A₄ independently denote a divalent cyclic group selected from1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; pyridine-2,5-diyl; pyrimidine-2,5-diyl;pyrazine-2,5-diyl; pyridazine-3,6-diyl; 1,4-cyclohexylene;1,3-dioxane-2,5-diyl; 1,3-dithiane-2,5-diyl; thiophene-2,5-diyl;thiazole-2,5-diyl; thiadiazole-2,5-diyl; benzoxazole-2,5-diyl;benzoxazole-2,6-diyl; benzothiazole-2,5-diyl; benzothiazole-2,6-diyl;quinoxaline-2,6-diyl; quinoline-2,6-diyl; 2,6-naphthylene;indan-2,5-diyl; 2-alkylindan-2,5-diyl having a linear or branched alkylgroup having 1-18 carbon atoms; indanone-2,6-diyl;2-alkylindanone-2,6-diyl having a linear or branched alkyl group having1-18 carbon atoms; coumaran-2,5-diyl; and 2-alkylcumaran-2,5-diyl havinga linear or branched alkyl group having 1-18 carbon atoms; and

X₁ and X₂ independently denote a single bond, --COO--, --OCO--, --CH₂O--, --OCH₂ --, --CH₂ CH₂ --, --CH═CH-- or --C.tbd.C--.

According to the present invention, there is further provided a liquidcrystal composition containing at least one species of theabove-mentioned mesomorphic compound.

The present invention provides a liquid crystal device comprising a pairof electrode plates and the liquid crystal composition described abovedisposed between the electrode plates.

The present invention further provides a liquid crystal apparatusincluding the liquid crystal device, particularly including a displaypanel comprising the liquid crystal device.

The present invention still further provides a display method using theliquid crystal composition described above and controlling the alignmentdirection of liquid crystal molecules to effect display.

We have found that a mesomorphic quinoxaline compound, represented bythe formula (I) having at least two ether groups between alkylene groupsin a specific terminal alkoxy perfluoroalkyl group provides a widertemperature range showing a mesomorphic phase, a good compatibility withanother compound and a low viscosity, and thus is suitable as acomponent of a liquid crystal composition, particularly a ferroelectricliquid crystal composition and a liquid crystal device including theliquid crystal composition which provide good display characteristicsbased on improvements in various characteristics such as an alignmentcharacteristic, switching characteristic, responsiveness, atemperature-dependence of response speed, a contrast, and a stability ofa layer structure of a liquid crystal. As the mesomorphic compound ofthe formula (I) according to the present invention has a goodcompatibility with another (mesomorphic or optically active) compoundused herein, it is possible to use the mesomorphic compound of theformula (I) for controlling various properties such as spontaneouspolarization, SmC* pitch, Ch pitch, a temperature range showing amesomorphic phase, optical anisotropy, a tilt angle and dielectricanisotropy, with respect to a liquid crystal mixture or composition.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a liquid crystal device using aliquid crystal composition assuming a chiral smectic phase;

FIGS. 2 and 3 are schematic perspective views of a device cellembodiment for illustrating the operation principle of a liquid crystaldevice utilizing ferroelectricity of a liquid crystal composition;

FIG. 4 is a schematic view for illustrating a tilt angle H in aferroelectric liquid crystal with a helical structure.

FIG. 5A shows unit driving waveforms used in an embodiment of thepresent invention; FIG. 5B is time-serial waveforms comprising asuccession of such unit waveforms;

FIG. 6 is an illustration of a display pattern obtained by an actualdrive using the time-serial waveforms shown in FIG. 5B;

FIG. 7 is a block diagram showing a display apparatus comprising aliquid crystal device utilizing ferroelectricity of a liquid crystalcomposition and a graphic controller; and

FIG. 8 is a time chart of image data communication showing timecorrelation between signal transfer and driving with respect to a liquidcrystal display apparatus and a graphic controller.

DETAILED DESCRIPTION OF THE INVENTION

Hereinbelow, the respective symbols m, n, p, q, Y₁, A₁, A₂, A₃, A₄, X₁,X₂ and R₁ have the meanings defined in the description with respect tothe mesomorphic compound of the formula (I), unless expressly indicatedotherwise.

The mesomorphic compound of the formula (I) according to the presentinvention is characterized by a specific alkoxy perfluoroalkyl group:C_(m) F_(2m+1) (CH₂)_(n) O(CH₂)_(p) O(CH₂)_(q) in which at least twoether groups is disposed between alkylene group.

The mesomorphic compound of the formula (I) may be an optically activecompound or an optically inactive compound.

When the mesomorphic compound of the formula (I) is an opticallyinactive compound, R₁ in the formula (I) may preferably be H, halogen,CN, or a linear, branched or cyclized alkyl group having 1-20 carbonatoms capable of including at least one --CH₂ -- group which can bereplaced with --O--, --S--, --CO--, --CH(CN)--, --CH═CH-- or --C.tbd.C--provided that heteroatoms are not adjacent to each other and capable ofincluding at least one H which can be replaced with F.

When the mesomorphic compound of the formula (I) is an optically activecompound, R₁ in the formula (I) may preferably be a linear, branched orcyclized alkyl group having 2-30 carbon atoms capable of including atleast one --CH₂ -- group which can be replaced with --O--, --S--,--CO--, --CH(Cl)--, --CH(CN)--, --CCH₃ (CN)--, --CH═CH-- or --C.tbd.C--provided that heteroatoms are not adjacent to each other and capable ofincluding at least one H which can be replaced with F.

When the mesomorphic compound of the formula (I) is an optically activecompound or an optically inactive compound, preferred examples of such amesomorphic compound may include those comprising any one of themesomorphic compounds (Ia) to (Ic) of the formula (I) below in view ofcontrol of various properties including a temperature range of amesomorphic phase, miscibility, viscosity and alignment characteristic.

Compound (Ia) wherein A₁ is --A₂ -- and A₂ is a divalent cyclic groupselected from 1,4-phenylene capable of having one or two substituentscomprising F, Cl, Br, CH₃, CF₃ or CN; 1,4-cyclohexylene;quinoxaline-2,6-diyl; quinoline-2,6-diyl; and 2,6-naphthylene;

Compound (Ib) wherein A₁ is --A₂ --X₁ --A₃ -- in which at least one ofA₂ and A₃ is a divalent cyclic group selected from 1,4-phenylene capableof having one or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN;1,4-cyclohexylene; pyridine-2,5-diyl; and pyrimidine-2,5-diyl; and

Compound (Ic) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which atleast one of A₂, A₃ and A₄ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN and the remainder ofA₂, A₃ and A₄ is a divalent group selected from 1,4-phenylene capable ofhaving one or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN;pyridine-2,5-diyl; pyrimidine-2,5-diyl; 1,4-cyclohexylene;thiazole-2,5-diyl; thiadiazole-2,5-diyl; indan-2,5-diyl; andcoumaran-2,5-diyl.

Further preferred examples of the mesomorphic compound of the formula(I) which is optically active or optically inactive (not opticallyactive) may include those comprising any one of the followingmesomorphic compounds (Iba) to (Ice) of the formula (I):

Compounds (Iba) wherein A₁ is --A₂ --X₁ --A₃ -- in which each of A₂ andA₃ is 1,4-phenylene capable of having one or two substituents comprisingF, Cl, Br, CH₃, CF₃ or CN; and X₁ is a single bond, --COO--, --CH₂ O--,--CH₂ CH₂ -- or --C═C--;

Compound (Ibb) wherein A₁ is --A₂ --X₁ --A₃ -- in which one of thegroups A₂ and A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; the other group A₂ orA₃ is a divalent cyclic group selected from pyridine-2,5-diyl,pyrimidine-2,5-diyl, pyrazine-2,5-diyl, pyridazine-3,6-diyl,1,4-cyclohexylene, thiophene-2,5-diyl, thiazole-2,5-diyl,thiadiazole-2,5-diyl, benzoxazole-2,5-diyl, benzothiazole-2,6-diyl,quinoxaline-2,6-diyl, quinoline-2,6-diyl, 2,6-naphthylene,indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond;

Compound (Ibc) wherein A₁ is --A₂ --X₁ --A₃ -- in which one of thegroups A₂ and A₃ is pyridine-2,5-diyl; the other group A₂ or A₃ is adivalent cyclic group selected from 1,4-cyclohexylene, 2,6-naphthylene,indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond;

Compound (Ibd) wherein A₁ is --A₂ --X₁ --A₃ -- in which one of thegroups A₂ and A₃ is pyrimidine-2,5-diyl; the other group A₂ or A₃ is adivalent cyclic group selected from 1,4-cyclohexylene, 2,6-naphthylene,indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond;

Compound (Ica) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which eachof A₂, A₃ and A₄ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and at least one ofX₁ and X₂ is a single bond;

Compound (Icb) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which two ofA₂, A₃ and A₄ is 1,4-phenylene capable of having one or two substituentscomprising F, Cl, Br, CH₃, CF₃ or CN; and the remainder of A₂, A₃ and A₄is a divalent cyclic group selected from pyridine-2,5-diyl,pyrimidine-2,5-diyl, 1,4-cyclohexylene, thiazole-2,5-diyl,thiadiazole-2,5-diyl, indan-2,5-diyl and coumaran-2,5-diyl; and X₁ andX₂ are a single bond;

Compound (Icc) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one ofthe groups A₂ and A₄ is pyridine-2,5-diyl and the other group A₂ or A₄is a divalent cyclic group selected from 1,4-phenylene capable of havingone or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN,1,4-cyclohexylene, thiophene-2,5-diyl, and indan-2,5-diyl; A₃ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and one of the groups X₁ and X₂ is a single bondand the other group X₁ or X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --;

Compound (Icd) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one ofthe groups A₂ and A₄ is pyrimidine-2,5-diyl and the other group A₂ or A₄is a divalent cyclic group selected from 1,4-phenylene capable of havingone or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN,1,4-cyclohexylene, thiophene-2,5-diyl, and indan-2,5-diyl; A₃ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and one of the groups X₁ and X₂ is a single bondand the other group X₁ or X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --; and

Compound (Ice) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one ofthe groups A₂ and A₄ is 1,4-cyclohexylene and the other group A₂ or A₄is a divalent cyclic group selected from 1,4-phenylene capable of havingone or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN,1,4-cyclohexylene, thiophene-2,5-diyl, and indan-2,5-diyl; A₃ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and one of the groups X₁ and X₂ is a single bondand the other group X₁ or X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --.

When the mesomorphic compound of the formula (I) is an opticallyinactive compound, such a compound may, in particular, preferably be anyone of the following mesomorphic compounds (Ibaa) to (Icea) of theformula (I):

Compounds (Ibaa) wherein A₁ is --A₂ --X₁ --A₃ -- in which each of A₂ andA₃ is 1,4-phenylene capable of having one or two substituents comprisingF, Cl, Br, CH₃, CF₃ or CN; and X₁ is a single bond, --COO--, --CH₂ O--,--CH₂ CH₂ -- or --C.tbd.C--;

Compound (Ibba) wherein A₁ is --A₂ --A₁ --A₃ -- in which A₂ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; A₃ is a divalent cyclic group selected frompyridine-2,5-diyl, pyrimidine-2,5-diyl, pyrazine-2,5-diyl,pyridazine-3,6-diyl, 1,4-cyclohexylene, thiophene-2,5-diyl,thiazole-2,5-diyl, thiadiazole-2,5-diyl, benzoxazole-2,5-diyl,benzothiazole-2,6-diyl, quinoxaline-2,6-diyl, quinoline-2,6-diyl,2,6-naphthylene, indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is asingle bond;

Compound (Ibca) wherein A₁ is --A₂ --X₁ --A₃ -- in which A₂ ispyridine-2,5-diyl; A₃ is a divalent cyclic group selected from1,4-cyclohexylene, 2,6-naphthylene, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond;

Compound (Ibda) wherein A₁ is --A₂ --X₁ --A₃ -- in which A₂ ispyrimidine-2,5-diyl; A₃ is a divalent cyclic group selected from1,4-cyclohexylene, 2,6-naphthylene, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond;

Compound (Icaa) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which eachof A₂, A₃ and A₄ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and at least one ofX₁ and X₂ is a single bond;

Compound (Icba) wherein A₁ is --A₂ --X₁ --A₃ --X₂ ----A₄ -- in which twoof A₂, A₃ and A₄ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and the remainder ofA₂, A₃ and A₄ is a divalent cyclic group selected frompyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,4-cyclohexylene,thiazole-2,5-diyl, thiadiazole-2,5-diyl, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ and X₂ are a single bond;

Compound (Icca) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which A₂ ispyridine-2,5-diyl; A₄ is a divalent cyclic group selected from1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN, 1,4-cyclohexylene, thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; X₁ is a single bond;and X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --;

Compound (Icda) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which A₂ ispyrimidine-2,5-diyl; A₄ is a divalent cyclic group selected from1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN, 1,4-cyclohexylene, thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; X₁ is a single bond;and X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --; and

Compound (Icea) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which A₂ is1,4-cyclohexylene; A₄ is a divalent cyclic group selected from1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN, 1,4-cyclohexylene, thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; X₁ is a single bond;and X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --.

When the mesomorphic compound of the formula (I) is optically active ornot optically active, at least one of A₂ and A₃ may preferably be adivalent cyclic group selected from thiophene-2,5-diyl;thiazole-2,5-diyl; thiadiazole-2,5-diyl; benzoxazole-2,5-diyl;benzoxazole-2,6-diyl; benzothiazole-2,5-diyl; benzothiazole-2,6-diyl;quinoxaline-2,6-diyl; quinoline-2,6-diyl; indan-2,5-diyl;2-alkylindan-2,5-diyl having a linear or branched alkyl group having1-18 carbon atoms; indanone-2,6-diyl; 2-alkylindanone-2,6-diyl having alinear or branched alkyl group having 1-18 carbon atoms;coumaran-2,5-diyl; and 2-alkylcumaran-2,5-diyl having a linear orbranched alkyl group having 1-18 carbon atoms.

When the mesomorphic compound of the formula (I) is an opticallyinactive compound, m may preferably be an integer of 1-12 and n and peach may preferably be integer of 1-5 provided that m+n+p+q≦15; and R₁in the formula (I) may preferably be any one of the following groups (i)to (vii): ##STR1## in which a is an integer of 1-16; m' is an integer of1-12; n', p' and q' each are an integer of 1-5; d, g and i each are aninteger of 0-7; b, e and h each are an integer of 1-10; f is 0 or 1 withthe proviso that m'+n'+p'+q'≦15, b+d≦16, e+f+g≦16, and h+i≦16, and Y₁ 'is a single bond, --O--, --COO-- or --OCO--.

When the mesomorphic compound of the formula (I) is an optically activecompound, R₁ in the formula (I) may preferably be any one of thefollowing optically active groups (i*) to (x*): ##STR2## in which a, sand d each are an integer of 1-16; b, g, h and t each are an integer of0-10; e and f each are an integer of 0-7 with the proviso that a+b≦16and d+e+f≦15, Z₁ is CH₃, CF₃, F or CN; Y₂ is a single bond, --O--,--COO-- or --OCO--; Y₃ is a single bond, --O--, --COO--, --OCO--, --CH₂O-- or --CH₂ OCO--; and * denotes the location of an optically activecenter.

R₁ may be a cyclized alkyl group (e.g., the groups (ix*) to (x*) asdescribed above. Herein, "cyclized alkyl group" means a cyclic alkylgroup or an alkyl group having a partially cyclized structure in whichthe cyclized structure can be constituted by methylene group and/or atleast one heteroatom (e.g., oxygen) and at least one methylene group inthe alkyl group can be replaced with --O-- or --CO--.

The mesomorphic compound of the formula (I) (optically active oroptically inactive) may generally be synthesized through, e.g., thefollowing reaction schemes. ##STR3## (TsCl: p-toluenesulfonic acidchloride (tosyl chloride))

Herein, the term "mesomorphic compound" covers not only a compoundassuming a mesomorphic (liquid crystal) phase but also a compound notassuming a mesomorphic phase per se as long as a liquid crystalcomposition containing such a compound assumes a mesomorphic phase.

Specific examples of the optically inactive mesomorphic compound of theformula (I) may include those represented by the following structuralformulae (Example Compounds Nos. 1 to 253) including abbreviations forrespective cyclic groups listed below. ##STR4##

In the above, t, q and h each are an integer of 0-10.

    __________________________________________________________________________    C.sub.m F.sub.2m+1 (CH.sub.2).sub.n O(CH.sub.2).sub.p O(CH.sub.2).sub.q    --Y.sub.1           A.sub.1    No. m n  p q --Y.sub.1 --                        A.sub.2                               X.sub.1 A.sub.3                                           X.sub.2                                                 A.sub.4                                                      R.sub.1    __________________________________________________________________________    1   1 1  1 2 --O--  Ph     --      Ph  --    --   OC.sub.5 H.sub.13    2   1 2  1 2 --O--  Py2    --      Ph  --    --   C.sub.5 H.sub.11    3   1 1  2 1 --     Ph     --      Py1 --    --   C.sub.7 H.sub.15    4   1 3  2 7 --O--  Ep2    --      Ph  --    --   C.sub.8 H.sub.17    5   1 4  2 4 --O--  Py2    --      Pb  --OCO--                                                 Ph   C.sub.10 H.sub.21    6   1 1  2 3 --O--  Ph     --      Btb1                                           --    --   C.sub.13 H.sub.27    7   1 1  2 2 --O--  Ph     --COO-- Ph2F                                           --    --   C.sub.7 H.sub.15    8   1 2  2 2 --O--  Ph     --      py1 --    --   C.sub.5 H.sub.13    9   1 1  2 2 --     Ph     --COO-- Ph  --    --   OCOC.sub.9 H.sub.19    10  1 1  2 2 --O--  Ph     --      Ph  --    Py1  C.sub.12 H.sub.25    11  1 1  2 8 --O--  Ph     --      Py1 --    --   OC.sub.6 H.sub.13    12  1 1  3 2 --O--  Ph     --      Cy  --    --   C.sub.8 H.sub.17    13  1 3  3 3 --O--  Ph     --      Py2 --    --   C.sub.4 H.sub.9    14  1 2  3 2 --COO--                        Ph     --OCO-- Ph  --    --   OCH.sub.2 CH(CH.sub.3)C.                                                      sub.2 H.sub.5    15  1 1  3 2 --     Ph     --      Py1 --    --   C.sub.11 H.sub.23    16  1 1  3 10                 --O--  Ph     --      Ep1 --    --   C.sub.5 H.sub.13    17  1 1  4 2 --O--  Py2    --      Ph  CH.sub.2 CH.sub.2                                                 Tn   C.sub.7 H.sub.15    18  1 2  4 2 --O--  Ph     CH═CH                                       Ph  --    --   C.sub.5 H.sub.13    19  1 1  4 2 --O--  Ph     --      Boa1                                           --    --   C.sub.3 H.sub.7    20  1 1  4 2 --O--  Ph     --      Bta1                                           --    --   C.sub.15 H.sub.31    21  1 1  8 1 --     Py2    --      Cm2 --    --   C.sub.5 H.sub.13    22  1 1  10               3 --     Ph     --      Ph  --    Pr1  C.sub.9 H.sub.19    23  1 2  13               2 --O--  Ph     --OCH.sub.2 --                                       Ph  --    --   OC.sub.5 H.sub.11    24  2 1  1 2 --O--  Ph     --      Py1 --    Ph   C.sub.5 H.sub.13    25  2 1  2 2 --O--  Ph     --      --  --    --   OC.sub.8 H.sub.17    26  2 1  2 2 --O--  Ph     --      Gp1 --    --   C.sub.10 H.sub.21    27  2 1  2 4 --O--  Ph     --      Pr1 --    --   C.sub.11 H.sub.23    28  2 2  2 2 --O--  Py2    --      Ph  --OCO--                                                 Cy   C.sub.5 H.sub.13    29  2 1  2 2 --O--  Ph     --      Py1 --    --   OCH.sub.2 C.sub.5                                                      F.sub.13    30  2 1  2 1 --OCO--                        Py2    --      Cy  --    --   C.sub.10 H.sub.21    31  2 2  2 2 --O--  Ph     CH.sub.2 CH.sub.2                                       Ph  --    --   OCH.sub.2 C.sub.9                                                      F.sub.19    32  2 6  2 6 --O--  Ph     --      Ph3F                                           --    --   C.sub.5 H.sub.13    33  2 1  2 2 --     Ph     --      Py2 --    --   C.sub.8 H.sub.17    34  2 1  2 2 --O--  Pr2    --      Ph  --OCO--                                                 Ph   C.sub.5 H.sub.13    35  2 1  2 2 --O--  Ph     --      Ph  --    --   C.sub.16 H.sub.33    36  2 2  2 2 --O--  Ph     --      Py1 --    --   C.sub.13 H.sub.27    37  2 1  2 4 --O--  Ph     --      Py1 --    --   OC.sub.5 H.sub.11    38  2 1  2 7 --OCO--                        Ph     --      Ep2 --    --   C.sub.5 H.sub.13    39  2 8  3 2 --O--  Ph     --COO-- Ph  --    Tn   C.sub.4 H.sub.9    40  2 1  3 3 --     Ph     --CH.sub.2 O--                                       Ph  --    --   OCH(CH.sub.3)CH.sub.2                                                      OC.sub.3 H.sub.7    41  2 3  3 5 --O--  Ph     --      Py1 --    --   C.sub.10 H.sub.21    42  2 1  4 2 --O--  Ph     --      Py1 --    --   C.sub.10 H.sub.21    43  2 1  4 1 --     Ph     --      Tz1 --    Ph   C.sub.5 H.sub.13    44  2 2  4 3 --     Ph     --COO-- Ph  --    --   OC.sub.8 H.sub.17    45  2 3  5 4 --O--  Ph     --      Ph  --    Py1  C.sub.5 H.sub.13    46  2 1  5 2 --O--  Py2    --      Ph  CH.sub.2 CH.sub.2                                                 Cy   C.sub.7 H.sub.15    47  2 1  8 2 --O--  Ph     --      Pd  --    --   C.sub.5 H.sub.13    48  2 1  9 1 --O--  Py2    --      Cm2 --    --   C.sub.10 H.sub.21    49  2 1  13               2 --OCO--                        Ph     --C.tbd.C--                                       Ph  --    --   OC.sub.11 H.sub.23    50  2 1  14               1 --     Ph     --      Ep1 --    --   C.sub.10 H.sub.21    51  3 2  1 2 --C.tbd.C--                        Ph     --      Py1 --    --   C.sub.5 H.sub.11    52  3 1  1 2 --O--  Ph     --      Cy  --    --   C.sub.9 H.sub.19    53  3 1  2 5 --O--  Ph     --      Ph  --OCO--                                                 Ph2TF                                                      C.sub.4 H.sub.9    54  3 1  2 2 --O--  Ph     --      Py1 --    --   C.sub.12 H.sub.25    55  3 1  2 2 --     Ph     --OCO-- Ph  --    --   C.sub.2 H.sub.5    56  3 1  2 4 --O--  Ep2    --      --  --    --   OCOC.sub.5 H.sub.13    57  3 1  2 2 --O--  Ph     --      Ph  --    Cy   C.sub.8 H.sub.17    58  3 1  2 2 --O--  Ph     --      Py2 --    Ph   C.sub.5 H.sub.13    59  3 2  2 2 --O--  Ph     --      Np  --    --   C.sub.7 H.sub.15    60  3 1  2 6 --O--  Pr2    --      Ph  --OCO--                                                 Cy   C.sub.5 H.sub.11    61  3 6  2 3 --O--  Ph     --      Pr1 --    --   OC.sub.11 H.sub.23    62  3 11 2 2 --O--  Ph     --COO-- Ph  --    Ph   C.sub.12 H.sub.25    63  3 1  3 2 --O--  Py2    --      Ph  --OCO--                                                 Tn   C.sub.3 H.sub.7    64  3 1  3 2 --OCH.sub.2 --                        Ph     --COO-- Ph  --    --   C.sub.5 H.sub.13    65  3 3  3 3 --O--  Ph     --      Tz2 --    Ph   C.sub.8 H.sub.17    66  3 1  3 1 --     Ph     --      Py1 --    --   C.sub.9 H.sub.19    67  3 1  2 2 --O--  Ph     --      Py1 --    --   C.sub.10 H.sub.21    68  3 1  2 2 --O--  Np     --      Tz2 --    --   C.sub.5 H.sub.13    69  3 1  2 2 --O--  Ph     --      Btb1                                           --    --   C.sub.8 H.sub.17    70  3 2  2 2 --O--  Ph     --      Py1 --    --   OC.sub.10 H.sub.21    71  3 1  2 2 --     Ph     --      Boa2                                           --    --   C.sub.10 H.sub.21    72  3 3  5 3 --O--  Pr2    --      Cy  --    --   C.sub.10 H.sub.21    73  3 1  5 4 --O--  Ph     --OCH.sub.2 --                                       Ph  --    --   C.sub.12 H.sub.25    74  3 1  6 2 --O--  Ph     --      Ep1 --    --   C.sub.5 H.sub.13    75  3 1  6 2 --OCH.sub.2 --                        Ph     --      Pr1 --    --   C.sub.8 H.sub.17    76  3 1  8 2 --O--  Ph     --      Ph  --    Ph   C.sub.5 H.sub.11    77  4 1  1 1 --     Ph     --OCO-- Ph  --    --   O(CH.sub.2).sub.5                                                      CH(CH.sub.3)CH.sub.3    78  4 1  2 2 --O--  Py2    --      Boa2                                           --    Ph   C.sub.9 H.sub.19    79  4 2  2 2 --O--  Ph     --      Py2 --    --   C.sub.5 H.sub.13    80  4 1  2 2 --O--  Pr2    --      Ph  --OCO--                                                 Tn   C.sub.4 H.sub.9    81  4 1  2 1 --O--  Ph     CH.sub.2 CH.sub.2                                       Ph  --    --   C.sub.9 H.sub.19    82  4 1  2 5 --O--  Ph     --      Py1 --    --   C.sub.5 H.sub.13    83  4 1  2 2 --O--  Cy     --      Ph  --OCH.sub.2 --                                                 Ph   C.sub.7 H.sub.15    84  4 1  2 2 --O--  Ph     --      Ph  --    --   COOC.sub.4 H.sub.9    85  4 1  2 2 --O--  Ph     --      Ph23F                                           --    --   C.sub.5 H.sub.13    86  4 1  2 1 --     Ph     --      Td  --    Ph   C.sub.8 H.sub.17    87  4 1  2 2 --     Py2    --      Ph  CH.sub.2 CH.sub.2                                                 Ph   C.sub.10 H.sub.21    88  4 1  2 3 --     Py2    --      Btb2                                           --    Ph   C.sub.5 H.sub.11    89  4 1  2 4 --O--  Py2    --      Ph3F                                           --    --   C.sub.5 H.sub.13    90  4 2  3 2 --O--  Ph     --CH.sub.2 O--                                       Ph  --    --   C.sub.3 H.sub.7    91  4 4  3 4 --O--  Ph     --      Id2 --    --   C.sub.8 H.sub.17    92  4 1  3 2 --O--  Cy     --      Ph  --OCO--                                                 Id2  C.sub.5 H.sub.11    93  4 1  3 2 --O--  Ph     --      Gp1 --    --   C.sub.11 H.sub.23    94  4 3  3 3 --O--  Ph     --      Py1 --    --   C.sub.7 H.sub.15    95  4 1  3 2 --O--  Ph     --      Cy  --    --   OC.sub.9 H.sub.19    96  4 1  3 2 --     Ph     --COO-- Ph  --    --   OCH.sub.2 C.sub.8                                                      F.sub.17    97  4 1  4 2 --O--  Py2    --      Np  --    --   OCH.sub.2 C.sub.10                                                      F.sub.21    98  4 2  4 2 --O--  Ph     --      Dx2 --    Ph   C.sub.5 H.sub.13    99  4 1  4 2 --O--  Ph     --      Tz1 --    Ph   C.sub.5 H.sub.13    100 4 1  4 4 --O--  Gp2    --      --  --    --   C.sub.5 H.sub.13    101 4 1  4 2 --O--  Ph     --      Ph  --    --   C.sub.14 H.sub.29    102 4 1  5 2 --O--  Ph     --      Dt1 --    Ph   C.sub.10 H.sub.21    103 4 2  5 2 --OCO--                        Ph     --      Pa  --    --   C.sub.9 H.sub.19    104 4 1  6 1 --O--  Py2    --      Io2 --    --   C.sub.8 H.sub.17    105 4 1  6 2 --O--  Ph     --      Ph  --    Cy   C.sub.5 H.sub.13    106 4 2  7 2 --O--  Ph     --      Py1 --    --   C.sub.5 H.sub.13    107 4 1  10               1 --O--  Ph     --      Ph  --    Py1  C.sub.5 H.sub.11    108 3 2  11               2 --O--  Py2    --      Ph  --    --   C.sub.9 H.sub.19    109 5 1  1 2 --O--  Ph2F   --      Ph  --    Py1  C.sub.8 H.sub.17    110 5 2  2 4 --O--  Ph     --C.tbd.C--                                       Ph  --    --   C.sub.10 H.sub.21    111 5 1  2 2 --     Ph     --      Np  --    --   OC.sub.4 H.sub.9    112 5 1  2 2 --O--  Ph     --      Ph  --    Ph   C.sub.5 H.sub.13    113 5 1  2 2 --O--  Py2    --      Ph  --OCH.sub.2 --                                                 Id2  C.sub.9 H.sub.19    114 5 1  2 2 --O--  Ph     --OCH.sub.2 --                                       Ph  --    --   C.sub.10 H.sub.21    115 5 1  2 2 --O--  Py2    --      Ph  --OCO--                                                 Id2  C.sub.5 H.sub.13    116 5 1  2 2 --O--  Ph     --      Dt2 --    --   C.sub.5 H.sub.11    117 5 1  2 3 --O--  Ph     --      Tz1 --    Ph   C.sub.5 H.sub.11    118 5 1  2 2 --OCH.sub.2 --                        Ph     --      Pr2 --    --   C.sub.5 H.sub.13    119 5 1  2 2 --O--  Ph     --      Py1 --    Ph   OC.sub.9 H.sub.19    120 5 1  2 2 --O--  Cy     --      Ph  CH.sub.2 CH.sub.2                                                 Tn   C.sub.3 H.sub.17    121 5 1  2 1 --O--  Ph     --      Tn  --    --   C.sub.11 H.sub.23    122 5 3  2 3 --O--  Ph     --OCO-- Ph  --COO--                                                 Ph   C.sub.8 H.sub.17    123 5 1  2 2 --O--  Ph     --      Py1 --    --   C.sub.5 H.sub.13    124 5 1  3 2 --O--  Ph     --      Ph  --CH.sub.2 O--                                                 Ph   C.sub.7 H.sub.15    125 5 1  3 2 --O--  Ph     --      Ph  --    Tz1  C.sub.5 H.sub.13    126 5 1  3 2 --O--  Ph     --      Gp1 --    --   OC.sub.8 H.sub.17    127 5 1  3 2 --O--  Ph     --      Id2 --    --   C.sub.10 H.sub.21    128 5 2  3 2 --O--  Ph     --      Pr1 --    --   OCH.sub.2 CH(CH.sub.3)OC                                                      .sub.4 H.sub.9    129 5 1  3 2 --O--  Ph     --      Tz2 --    --   C.sub.5 H.sub.13    130 5 1  3 1 --     Ph     --      Btb1                                           --    --   C.sub.5 H.sub.11    131 5 1  4 2 --O--  Ph     --      Ep1 --    --   C.sub.13 H.sub.27    132 5 1  4 2 --O--  Ph     --      Cy  --    --   C.sub.9 H.sub.19    133 5 1  4 2 --O--  Ph     --      Bob1                                           --    --   C.sub.3 H.sub.7    134 5 2  4 2 --O--  Ph     --      Ph  --    --   COOC.sub.14 H.sub.29    135 5 1  5 2 --O--  Ph     --      Ep2 --    --   C.sub.7 H.sub.15    136 5 1  6 2 --O--  Cy     --      Ph  --OCO--                                                 Tn   C.sub.5 H.sub.13    137 5 1  7 4 --O--  Py2    --      Id2 --    --   C.sub.8 H.sub.17    138 6 1  1 2 --O--  Ph     --      Btb2                                           --    Cy   C.sub.5 H.sub.11    139 6 1  1 2 --O--  Cy     --      Ph  --OCH.sub.2 --                                                 Cy   C.sub.12 H.sub.25    140 6 1  1 4 --O--  Ph     --COO-- Ph  --    --   OC.sub.5 H.sub.13    141 6 1  2 2 --O--  Ph     --      Py1 --    --   C.sub.8 H.sub.17    142 6 1  2 2 --     Ph     --      Py2 --    Ph3Cl                                                      C.sub.9 H.sub.19    143 6 1  2 2 --O--  Ph     --C.tbd.C--                                       Ph  --    Ph   C.sub.10 H.sub.21    144 6 1  2 2 --O--  Py2    --      Ph  --OCH.sub.2 --                                                 Tn   C.sub.7 H.sub.15    145 6 1  2 2 --COO--                        Ph     --      Gp2 --    --   C.sub.5 H.sub.13    146 6 1  2 1 --O--  Ph     --      Pr2 --    --   C.sub.9 H.sub.19    147 6 1  2 2 --O--  Np     --      --  --    --   C.sub.10 H.sub.21    148 6 3  2 5 --O--  Ph     --      Pa  --    Ph   C.sub.5 H.sub.13    149 6 1  2 4 --O--  Ph     --      Py2 --    Ph   C.sub.5 H.sub.11    150 6 2  2 2 --O--  Ph     --      Ph  --    Py1  C.sub.7 H.sub.15    151 6 1  3 2 --O--  Ph     --OCO-- Ph  --    --   C.sub.10 H.sub.21    152 6 1  3 2 --O--  Ph     --      Tz2 --    Ph   C.sub.4 H.sub.9    153 6 2  3 2 --O--  Ph     CH.sub.2 CH.sub.2                                       Ph  --    --   C.sub.12 H.sub.25    154 6 1  3 1 --O--  Ph     --OC--  Ph.sub.3 F                                           --    Py1  C.sub.5 H.sub.13    155 6 1  3 2 --O--  Ph     --      Tz2 --    Ph   C.sub.8 H.sub.17    156 6 1  4 2 --OCO--                        Ph     --      Ep1 --    --   C.sub.9 H.sub.19    157 6 1  4 2 --O--  Ph     --      Pr1 --    --   C.sub.5 H.sub.11    158 6 2  4 2 --O--  Pr2    --      Ph  --OCO--                                                 Id2  C.sub.7 H.sub.15    159 6 1  5 2 --O--  Ph     --      Py1 --    --   COOC.sub.8 H.sub.13    160 6 1  5 2 --O--  Cy     --      Ph  CH.sub.2 CH.sub.2                                                 Cy   C.sub.3 H.sub.7    161 6 2  6 2 --     Ph     --      Ph  --    Cm2  C.sub.12 H.sub.25    162 7 1  1 2 --     Ph     --      Ph  --    Py1  C.sub.5 H.sub.13    163 7 1  1 2 --O--  Pr2    --      Np  --    --   SC.sub.8 H.sub.17    164 7 1  1 2 --O--  Ph     --COO-- Ph  --    --   C.sub.9 H.sub.19    165 7 1  2 2 --O--  Cy     --      Ph  --OCH.sub.2 --                                                 Tn   C.sub.3 H.sub.7    166 7 1  2 2 --O--  Ph     --      Ph  --    Tn   C.sub.8 H.sub.17    167 7 1  2 2 --O--  Py2    --      Ph  --OCO--                                                 Ph   F    168 7 1  2 2 --O--  Py2    --      Ph  --OCH.sub.2 --                                                 Cy   C.sub.4 H.sub.9    169 7 1  2 2 --O--  Ph     --      Ph  --    Id2  C.sub.5 H.sub.11    170 7 2  2 2 --     Ph     --      Btb1                                           --    --   C.sub.5 H.sub.13    171 7 1  2 4 --O--  Ph     --      Py1 --    --   C.sub.7 H.sub.15    172 7 1  2 2 --O--  Py2    --      Id2 --    --   C.sub.10 H.sub.21    173 7 2  3 2 --O--  Ep2    --      --  --    --   C.sub.9 H.sub.19    174 7 1  3 2 --O--  Ph     --CH.sub.2 O--                                       Ph  --    --   C.sub.5 H.sub.13    175 7 1  3 2 --O--  Ph     --C.tbd.C--                                       Ph  --    Py1  C.sub.10 H.sub.21    176 7 2  4 2 --O--  Ph     --      Pr2 --    Ph   C.sub.12 H.sub.25    177 7 1  5 2 --     Ph     --      Pr1 --    --   C.sub.5 H.sub.13    178 7 1  6 2 --O--  Ph     --      Ph  --    Td   C.sub.5 H.sub.13    179 8 1  1 1 --     Pr2    --      Ph  --OCH.sub.2 --                                                 Cy   C.sub.8 H.sub.17    180 8 1  1 2 --O--  Ph     --COO-- Ph  --    --   C.sub.10 H.sub.21    181 8 1  1 1 --     Ph     --      Pa  --    --   C.sub.9.sub.H.sub.19    182 8 1  1 2 --O--  Ph     --      Ph  --    --   OCOC.sub.5 H.sub.13    183 8 1  2 2 --O--  Cy     --      Ph  CH.sub.2 CH.sub.2                                                 Ph   C.sub.3 H.sub.7    184 8 1  2 2 --O--  Ph     --      Ph  --    Py1  C.sub.5 H.sub.13    185 8 1  2 3 --O--  Ph     --      Cy  --    --   OCOCH.sub.2 CH(CN)C.sub.                                                      2 H.sub.5    186 8 1  2 2 --O--  Cy     --      Ph  --OCO--                                                 Cy   C.sub.8 H.sub.17    187 8 1  2 2 --O--  Ph     --      Td  --    --   C.sub.9 H.sub.19    188 8 1  2 2 --O--  Pr2    --      Ph  --OCO--                                                 Tn   C.sub.10 H.sub.21    189 8 1  3 2 --O--  Pr1    --      Id2 --    --   C.sub.5 H.sub.13    190 8 1  3 2 --O--  Ph     --      Cy  --    Ph   C.sub.7 H.sub.15    191 8 1  4 2 --O--  Ph     --      Py1 --    --   C.sub.9 H.sub.19    192 8 1  4 2 --O--  Py2    --      Ph  --OCH.sub.2 --                                                 Ph   C.sub.5 H.sub.13    193 8 2  5 2 --O--  Ph     --      Tz1 --    --   C.sub.5 H.sub.13    194 9 1  1 2 --O--  Ph     --      Bta1                                           --    --   C.sub.10 H.sub.21    195 9 1  1 2 --OCO--                        Ph     --      Pd  --    Ph   C.sub.12 H.sub.25    196 9 1  2 2 --O--  Py2    --      Ph  CH.sub.2 CH.sub.2                                                 Id2  C.sub.5 H.sub.13    197 9 1  2 2 --O--  Ph     --      Pr2 --    Ph   C.sub.4 H.sub.9    198 9 1  2 2 --O--  Ph     --      Bob2                                           --    Cy   OC.sub.8 H.sub.17    199 9 1  2 2 --O--  Btb2   --      Ph  --    --   C.sub.12 H.sub.25    200 9 1  3 2 --O--  Ph     --      Ph  --    --   C.tbd.CC.sub.9 H.sub.19    201 9 1  3 2 --O--  Ph     --      Pr2 --    --   C.sub.5 H.sub.13    202 9 1  4 3 --O--  Np     --      --  --    --   OC.sub.5 H.sub.11    203 9 1  5 2 --O--  Ph     --      Tn  --    --   C.sub.10 H.sub.21    204 10          1  1 2 --O--  Cy     --      Ph  --OCO--                                                 Ph   C.sub.5 H.sub.13    205 10          1  1 2 --     Ph     --      Tz1 --    Ph   C.sub.8 H.sub.17    206 10          1  2 2 --O--  Ph     --C.tbd.C--                                       Pd  --    --   C.sub.4 H.sub.9    207 10          2  2 2 --O--  Ph2M   --      Tz1 --    Ph   C.sub.3 H.sub.15                                                      CH═CH.sub.2    208 10          1  3 2 --O--  Ph     --      Py1 --    --   C.sub.9 H.sub.19    209 10          1  4 1 --     Ph     --      Ep1 --    --   OC.sub.10 H.sub.21    210 10          1  5 2 --OCO--                        Ph     --      Py2 --    Ph   C.sub.5 H.sub.13    211 11          1  1 2 --O--  Ph     --      Btb1                                           --    --   C.sub.5 H.sub.11    212 11          1  1 2 --O--  Ph     --      Ph2CN                                           --    --   OC.sub.5 H.sub.13    213 11          1  2 3 --O--  Ph     --COO-- Ph  --    --   C.sub.7 H.sub.15    214 11          1  2 2 --O--  Ep2    --      --  --    --   C.sub.9 H.sub.19    215 11          1  2 2 --O--  Ph     --      Dx1 --    --   C.sub.5 H.sub.13    216 11          1  3 2 --O--  Ph     --      Pr2 --    --   C.sub.12 H.sub.25    217 12          1  1 2 --     Boa2   --      Ph  --    --   OC.sub.4 H.sub.9    218 12          1  1 2 --O--  Pr2    --      Cm2 --    --   C.sub.7 H.sub.15    219 12          1  2 1 --O--  Ph     --      Ph  --    --   H    220 12          1  2 2 --O--  Ph     --      --  --    --   COOC.sub.10 H.sub.21    221 12          1  3 2 --O--  Ph     --      Btb1                                           --    --   C.sub.5 H.sub.11    222 13          1  1 2 --O--  Gp2    --      --  --    --   C.sub.5 H.sub.13    223 13          1  2 2 --O--  Ph     --      Py1 --    --   C.sub.3 H.sub.7    224 13          1  2 2 --O--  Ph     --      Tz1 --    Ph3B C.sub.4 H.sub.9    225 13          1  3 1 --     Cy     --      --  --    --   C.sub.2 H.sub.6    226 14          1  2 1 --OCO--                        Cy     --      Ph  --OCH.sub.2 --                                                 Id2  CH.sub.3    227 15          1  1 1 --O--  Ph     --      Ph2F                                           --    --   C.sub.5 H.sub.13    228 4 1  2 2 --O--  Ph     --      Py1 --    --   OCH.sub.2 (CF.sub.2).sub                                                      .4 CH.sub.2 OCH.sub.3    229 3 2  2 2 --O--  Ph     --      Ph  --    --   OCH.sub.2 (CF.sub.2).sub                                                      .2 CH.sub.2 OC.sub.4                                                      H.sub.9    230 4 1  2 2 --O--  Py2    --      Ph  --    --   C.sub.8 F.sub.17    231 3 1  2 2 --O--  Py2    --      Ph  --    --   OCH.sub.2 C.sub.5                                                      F.sub.11    232 3 1  3 1 --O--  Ph     --      Py1 --    --   C.sub.18 H.sub.37    233 3 1  4 2 --CH═CH--                        Ph     --      Ph  --    --   C.sub.5 H.sub.13    234 3 1  4 2 --O--  Py2    --      Ph  --    --   C.sub.10 H.sub.21    235 3 1  4 2 --O--  Ph     --      Py1 --    --   OC.sub.4 H.sub.9    236 3 2  4 3 --     Ph     --O--   Btb1                                           --    --   C.sub.5 H.sub.13    237 3 1  2 2 --O--  Ph     --      Ph  --    --   O(CH.sub.2 CH.sub.2                                                      O).sub.2 CH.sub.2                                                      C.sub.3 F.sub.7    238 4 2  3 2 --O--  Ph     --      Cy  --    --   (CH.sub.2 CH.sub.2                                                      CH.sub.2 O).sub.2                                                      CH.sub.2 CF.sub.3    239 3 2  2 3 --     Py2    --      Ph  --    --   (OCH.sub.2 CH.sub.2).sub                                                      .2 CH.sub.2 OCH.sub.2                                                      C.sub.3 F.sub.5    240 2 4  3 2 --COO--                        Pr2    --      Ph  --    --   (CH.sub.2 CH.sub.2                                                      O).sub.2 (CH.sub.2).sub.                                                      2 C.sub.3 F.sub.7    241 3 2  3 3 --O--  Ph     --      Pr1 --    --   O(CH.sub.2 CH.sub.2                                                      O).sub.2 CH.sub.2                                                      C.sub.4 F.sub.9    242 4 1  2 2 --O--  Ph     --      Py1  13   --   O(CH.sub.2 CH.sub.2                                                      O).sub.2 (CH.sub.2).sub.                                                      2 C.sub.1 F.sub.5    243 5 1  2 2 --     Pr1    --      Ph  --    --   (OCH.sub.2 CH.sub.2).sub                                                      .2 (CH.sub.2).sub.2                                                      OCH.sub.2 CF.sub.3    244 5 2  2 2 --     Ph     --      Py1 --    --   OC.sub.4 H.sub.8                                                      CF.sub.3    245 4 2  2 2 --O--  Ph     --      Py1 --    --   C.sub.5 H.sub.10                                                      C.sub.2 F.sub.5    246 1 3  2 3 --     Ph     --OCO-- Cy  --    --   C.sub.5 H.sub.11    247 2 1  2 4 --O--  Ph     --OCO-- Tn  --    --   C.sub.8 H.sub.17    248 1 5  2 2 --O--  Ph     --OCH.sub.2 --                                       Cy  --    --   OC.sub.3 H.sub.7    249 2 1  5 2 --O--  Ph     --OCO-- Cy  --    --   C.sub.4 H.sub.9    250 3 1  4 2 --     Ph     --OCH.sub.2 --                                       Cy  --    --   C.sub.5 F.sub.13    251 4 2  2 2 --     Ph     --OCO-- Tn  --    --   C.sub.5 H.sub.13    252 3 2  3 2 --O--  Ph     --OCO-- Cy  --    --   C.sub.3 H.sub.7    253 5 2  2 3 --     Ph     --CH.sub.2 CH.sub.2 --                                       Cy  --O-- --   C.sub.4 H.sub.9    __________________________________________________________________________

Specific examples of the optically active mesomorphic compound of theformula (I) may include those represented by the following structuralformulae (Ex. Comp. Nos. 1* to 231*) including the abbreviations forrespective cyclic groups described above.

    __________________________________________________________________________    C.sub.m F.sub.2m+1 (CH.sub.2).sub.n O(CH.sub.2).sub.p O(CH.sub.2).sub.q    Y.sub.1              A.sub.1    No.       m  n p  q Y.sub.1 A.sub.2                               X.sub.1                                      A.sub.3                                          X.sub.2                                                 A.sub.4                                                     R.sub.1    __________________________________________________________________________     1*       1  1 1  2 O       Ph    --     Ph  --     --                                                      ##STR5##     2*       1  2 1  2 O       Py2   --     Ph  --     --                                                      ##STR6##     3*       1  1 2  1 --      Ph    --     Py1 --     --                                                      ##STR7##     4*       1  3 2  7 O       Ep2   --     Ph  --     --                                                      ##STR8##     5*       1  4 2  4 O       Py2   --     Ph  OCO    Ph                                                      ##STR9##     6*       1  1 2  3 O       Ph    --     Btb1                                          --     --                                                      ##STR10##     7*       1  1 2  2 O       Ph    COO    Ph2F                                          --     --  OCOThf     8*       1  2 2  2 O       Py2   --     Ph  --     --                                                      ##STR11##     9*       1  1 2  2 --      Ph    COO    Ph  --     --                                                      ##STR12##     10*       1  1 2  2 O       Py2   --     Ph  --     Ph                                                      ##STR13##     11*       1  1 2  8 O       Py2   --     Ph  --     --                                                      ##STR14##     12*       1  1 3  2 O       Ph    --     Cy  --     --                                                      ##STR15##     13*       1  3 3  3 O       Ph    --     Ph  --     --  OCH.sub.2 Lc2(5,5)     14*       1  2 3  2 COO     Ph    OCO    Ph  --     --                                                      ##STR16##     15*       1  1 3  2 --      Py2   --     Ph  --     --                                                      ##STR17##     16*       1  1 3  10                 O       Ph    --     Ep1 --     --                                                      ##STR18##     17*       1  1 4  2 --      Tn    COO    Ph  --     Py1                                                      ##STR19##     18*       1  2 4  2 O       Ph    CHCH   Ph  --     --                                                      ##STR20##     19*       1  1 4  2 O       Ph    --     Boa1                                          --     --                                                      ##STR21##     20*       1  1 4  2 O       Bta2  --     Ph  --     --                                                      ##STR22##     21*       1  1 8  1 --      Py2   --     Cm2 --     --                                                      ##STR23##     22*       1  1 10 3 --      Ph    --     Ph  --     Pr1                                                      ##STR24##     23*       1  2 13 2 O       Ph    OCH.sub.2                                      Ph  --     --                                                      ##STR25##     24*       2  1 1  2 O       Ph    --     Py1 --     Ph                                                      ##STR26##     25*       2  1 2  2 O       Ph    --     --  --     --                                                      ##STR27##     26*       2  1 2  2 O       Ph    --     Gp1 --     --  OCH.sub.2 Lc1(8,0)     27*       2  1 2  4 O       Py2   --     Ph  --     --                                                      ##STR28##     28*       2  2 2  2 O       Py2   --     Ph  OCO    Cy                                                      ##STR29##     29*       2  1 2  2 OCO     Py2   --     Ph  --     --                                                      ##STR30##     30*       2  1 2  1 O       Py2   --     Cy  --     --                                                      ##STR31##     31*       2  2 2  2 O       Ph    CH.sub.2 CH.sub.2                                      Ph  --     --                                                      ##STR32##     32*       2  6 2  6 O       Ph    --     Ph3F                                          --     --  OCH.sub.2 La2(6,0)     33*       2  1 2  2 --      Ph    --     Py2 --     --                                                      ##STR33##     34*       2  1 2  2 O       Pr2   --     Ph  OCO    Ph                                                      ##STR34##     35*       2  1 2  2 O       Ph    --     Ph  --     --  OCH.sub.2 Thf     36*       2  2 2  2 O       Ph    --     Py1 --     --                                                      ##STR35##     37*       2  1 2  4 O       Ph    --     Py1 --     --                                                      ##STR36##     38*       2  1 2  7 OCO     Ph    --     Ep2 --     --                                                      ##STR37##     39*       2  8 3  2 O       Ph    COO    Ph  --     Tn                                                      ##STR38##     40*       2  1 3  3 --      Ph    CH.sub.2 O                                      Ph  --     --  ODp(2)     41*       2  3 3  5 O       Ph    --     Py1 --     --                                                      ##STR39##     42*       2  1 4  2 O       Ph    --     Py1 --     --                                                      ##STR40##     43*       2  1 4  1 --      Ph    --     Tz1 --     Ph                                                      ##STR41##     44*       2  2 4  3 --      Ph    COO    Ph  --     --                                                      ##STR42##     45*       2  3 5  4 O       Ph    --     Ph  --     Py1 OLc2(3,3)     46*       2  1 5  2 O       Py2   --     Ph  CH.sub.2 CH.sub.2                                                 Cy                                                      ##STR43##     47*       2  1 8  2 O       Ph    --     Pd  --     --                                                      ##STR44##     48*       2  1 9  1 O       Py2   --     Cm2 --     --                                                      ##STR45##     49*       2  1 13 2 OCO     Ph    CC     Ph  --     --  COOLa1(1,1)     50*       2  1 14 1 --      Ph    --     Ep1 --     --                                                      ##STR46##     51*       3  2 1  2 CC      Ph    --     Py1 --     --                                                      ##STR47##     52*       3  1 1  2 O       Ph    --     Cy  --     --                                                      ##STR48##     53*       3  1 2  5 O       Ph    --     Ph  OCO    Ph2TF                                                      ##STR49##     54*       3  1 2  2 O       Ph    --     Py1 --     --                                                      ##STR50##     55*       3  1 2  2 --      Ph    OCO    Ph  --     --                                                      ##STR51##     56*       3  1 2  4 O       Ep2   --     --  --     --                                                      ##STR52##     57*       3  1 2  2 O       Ph    --     Ph  --     Cy  OCH.sub.2 Lc1(6,0)     58*       3  1 2  2 O       Ph    --     Py2 --     Ph                                                      ##STR53##     59*       3  2 2  2 O       Ph    --     Np  --     --                                                      ##STR54##     60*       3  1 2  6 O       Pr2   --     Ph  OCO    Cy                                                      ##STR55##     61*       3  6 2  3 O       Ph    --     Pr1 --     --                                                      ##STR56##     62*       3  11            2  2 O       Ph    COO    Ph  --     Ph  OCOLa2(5,0)     63*       3  1 3  2 O       Py2   --     Ph  OCO    Tn                                                      ##STR57##     64*       3  1 3  2 OCH.sub.2                         Ph    COO    Ph  --     --                                                      ##STR58##     65*       3  3 3  3 O       Ph    --     Tz2 --     Ph                                                      ##STR59##     66*       3  1 3  1 --      Py2   --     Ph  --     --  OCODp(0)     67*       3  1 2  2 O       Ph    --     Py1 --     --                                                      ##STR60##     68*       3  1 2  2 CHCH    Ph    --     Ph  --     --                                                      ##STR61##     69*       3  1 2  2 O       Py2   --     Py  --     --                                                      ##STR62##     70*       3  2 2  2 O       Ph    --     Py1 --     --                                                      ##STR63##     71*       3  1 2  2 O       Ph    --     Td  --     --                                                      ##STR64##     72*       3  3 5  3 O       Pr2   --     Cy  --     --  OCH.sub.2 Thf     73*       3  1 5  4 O       Ph    OCH.sub.2                                      Ph  --     --                                                      ##STR65##     74*       3  1 6  2 O       Ph    --     Ep1 --     --                                                      ##STR66##     75*       3  1 6  2 OCH.sub.2                         Ph    --     Pr1 --     --                                                      ##STR67##     76*       3  1 8  2 O       Ph    --     Ph  --     Ph                                                      ##STR68##     77*       4  1 1  1 --      Ph    OCO    Ph  --     --                                                      ##STR69##     78*       4  1 2  2 O       Py2   --     Boa2                                          --     Ph                                                      ##STR70##     79*       4  2 2  2 O       Ph    --     Py1 --     --  OCH.sub.2 Lc2(1,1)     80*       4  1 2  2 O       Pr2   --     Ph  OCO    Tn                                                      ##STR71##     81*       4  1 2  1 O       Ph    CH.sub.2 CH.sub.2                                      Ph  --     --                                                      ##STR72##     82*       4  1 2  5 O       Ph    --     Py1 --     --                                                      ##STR73##     83*       4  1 2  2 O       Cy    --     Ph  OCH.sub.2                                                 Ph                                                      ##STR74##     84*       4  1 2  2 O       Ph    --     Ph  --     --                                                      ##STR75##     85*       4  1 2  2 O       Ph    --     Ph23F                                          --     --                                                      ##STR76##     86*       4  1 2  1 --      Ph    --     Td  --     Ph                                                      ##STR77##     87*       4  1 2  2 --      Py2   --     Ph  CH.sub.2 CH.sub.2                                                 Ph  OCH.sub.2 Lc2(1,1)     88*       4  1 2  3 --      Py2   --     Btb2                                          --     Ph                                                      ##STR78##     89*       4  1 2  2 O       Py2   --     Ph3F                                          --     --                                                      ##STR79##     90*       4  2 3  2 O       Ph    CH.sub.2 O                                      Ph  --     --                                                      ##STR80##     91*       4  4 3  4 O       Ph    --     Id2 --     --                                                      ##STR81##     92*       4  1 3  2 O       Cy    --     Ph  OCO    Id2                                                      ##STR82##     93*       4  1 3  2 O       Ph    --     Gp1 --     --  OCH.sub.2 La2(8,0)     94*       4  3 3  3 O       Ph    --     Py1 --     --                                                      ##STR83##     95*       4  1 3  2 O       Ph    --     Cy  --     --                                                      ##STR84##     96*       4  1 3  2 --      Ph    COO    Ph  --     --                                                      ##STR85##     97*       4  1 4  2 O       Py2   --     Np  --     --                                                      ##STR86##     98*       4  2 4  2 O       Ph    --     Dx2 --     Ph  OCOPla     99*       4  1 4  2 O       Ph    --     Tz1 --     Ph                                                      ##STR87##    100*       4  1 4  4 O       Gp2   --     --  --     --                                                      ##STR88##    101*       4  1 4  2 O       Ph    --     Ph  --     --  OCH.sub.2 La2(1,1)    102*       4  1 5  2 O       Ph    --     Dt1 --     Ph                                                      ##STR89##    103*       4  2 5  2 OCO     Ph    --     Pa  --     --                                                      ##STR90##    104*       4  1 6  1 O       Py2   --     Io2 --     --                                                      ##STR91##    105*       4  1 6  2 O       Ph    --     Ph  --     Cy  OCOThf    106*       4  2 7  2 O       Ph    --     Py1 --     --                                                      ##STR92##    107*       4  1 10 1 O       Ph    --     Ph  --     Py1                                                      ##STR93##    108*       4  2 10 2 O       Py2   --     Ph  --     --                                                      ##STR94##    109*       5  1 1  2 O       Ph2F  --     Ph  --     Py1                                                      ##STR95##    110*       5  1 2  4 O       Ph    CC     Ph  --     --  OCH.sub.2 Lc2(6,0)    111*       5  1 2  2 --      Ph    --     Np  --     --                                                      ##STR96##    112*       5  1 2  2 O       Ph    --     Ph  --     Ph                                                      ##STR97##    113*       5  1 2  2 O       Py2   --     Ph  OCH.sub.2                                                 Id2                                                      ##STR98##    114*       5  1 2  2 O       Ph    OCH.sub.2                                      Ph  --     --                                                      ##STR99##    115*       5  1 2  2 O       Py2   --     Ph  OCO    Id2                                                      ##STR100##    116*       5  1 2  2 OCH.sub.2                         Ph    --     Dt2 --     --  OCH.sub.2 La2(8,0)    117*       5  1 2  3 O       Ph    --     Tz1 --     Ph                                                      ##STR101##    118*       5  1 2  2 O       Ph    --     Pr1 --     --  OCH.sub.2 Lc1(2,2)    119*       5  1 2  2 O       Ph    --     Py1 --     Ph                                                      ##STR102##    120*       5  1 2  2 O       Cy    --     Ph  CH.sub.2 CH.sub.2                                                 Tn                                                      ##STR103##    121*       5  1 2  1 O       Ph    --     Tn  --     --                                                      ##STR104##    122*       5  3 2  3 O       Ph    OCO    Cy  --     --                                                      ##STR105##    123*       5  1 2  2 O       Ph    --     Py1 --     --  OCH.sub.2 La2(8,0)    124*       5  1 3  2 O       Ph    --     Ph  CH.sub.2 O                                                 Ph                                                      ##STR106##    125*       5  1 3  2 O       Ph    --     Ph  --     Tz1                                                      ##STR107##    126*       5  1 3  2 O       Ph    --     Gp1 --     --  OCODp(2)    127*       5  1 3  2 O       Ph    --     Id2 --     --                                                      ##STR108##    128*       5  2 3  2 O       Pr2   --     Ph  --     --                                                      ##STR109##    129*       5  1 3  2 O       Ph    --     Tz2 --     --                                                      ##STR110##    130*       5  1 3  1 --      Ph    --     Btb1                                          --     --                                                      ##STR111##    131*       5  1 4  2 O       Ep2   --     Ph  --     --                                                      ##STR112##    132*       5  2 4  2 O       Ph    --     Cy  --     --  OCH.sub.2 Lc2(5,0)    133*       5  1 4  2 O       Ph    --     Bob1                                          --     --                                                      ##STR113##    134*       5  2 4  2 O       Ph    --     Ph  --     --                                                      ##STR114##    135*       5  1 5  2 O       Ph    --     Ep2 --     --                                                      ##STR115##    136*       5  1 6  2 O       Cy    --     Ph  OCO    Tn  CH.sub.2 OLa1(6,0)    137*       5  1 7  4 O       Py2   --     Id2 --     --                                                      ##STR116##    138*       6  1 1  2 O       Ph    --     Btb2                                          --     Cy                                                      ##STR117##    139*       6  1 1  2 O       Cy    --     Ph  OCH.sub.2                                                 Cy                                                      ##STR118##    140*       6  1 1  4 OC      Ph    COO    Ph  --     --                                                      ##STR119##    141*       6  1 2  2 O       Ph    --     Py1 --     --  OCH.sub.2 La2(6,0)    142*       6  1 2  2 --      Ph    --     Py2 --     Ph3Cl                                                      ##STR120##    143*       6  1 2  2 O       Ph    CC     Ph  --     Ph                                                      ##STR121##    144*       6  1 2  2 O       Py2   --     Ph  OCH.sub.2                                                 Tn                                                      ##STR122##    145*       6  1 2  2 COO     Ph    --     Gp2 --     --  OCH.sub.2 Lc2(1,1)    146*       6  1 2  1 O       Ph    --     Pr2 --     --                                                      ##STR123##    147*       6  1 2  2 O       Np    --     --  --     --                                                      ##STR124##    148*       6  3 2  5 O       Ph    --     Pa  --     Ph                                                      ##STR125##    149*       6  1 2  4 O       Ph    --     Py2 --     Ph                                                      ##STR126##    150*       6  2 2  2 O       Ph    --     Ph  --     Py1                                                      ##STR127##    151*       6  1 3  2 O       Ph    OCO    Ph  --     --  OCH.sub.2 La2(4,0)    152*       6  1 3  2 O       Ph    --     Tz2 --     Ph                                                      ##STR128##    153*       6  2 3  2 O       Ph    CH.sub.2 CH.sub.2                                      Ph  --     --                                                      ##STR129##    154*       6  1 3  1 O       Ph    OCO    Ph3F                                          --     Py1 OCOThf    155*       6  1 3  2 O       Ph    --     Tz2 --     Ph                                                      ##STR130##    156*       6  1 4  2 OCO     Ph    --     Ep1 --     --                                                      ##STR131##    157*       6  1 4  2 O       Ph    --     Pr1 --     --                                                      ##STR132##    158*       6  2 4  2 O       Pr2   --     Ph  OCO    Id2                                                      ##STR133##    159*       6  1 5  2 O       Ph    --     Py1 --     --  OCODp(0)    160*       6  1 5  2 O       Cy    --     Ph  CH.sub.2 CH.sub.2                                                 Cy                                                      ##STR134##    161*       6  2 6  2 --      Ph    --     Ph  --     Cm2 COOCH.sub.2 La1(3,3)    162*       7  1 1  2 --      Ph    --     Ph  --     Py1                                                      ##STR135##    163*       7  1 1  2 O       Pr2   --     Np  --     --                                                      ##STR136##    164*       7  1 1  2 O       Ph    COO    Ph  --     --                                                      ##STR137##    165*       7  1 2  2 O       Cy    --     Ph  OCH.sub.2                                                 Tn                                                      ##STR138##    166*       7  1 2  2 --      Tn    COO    Ph  --     Ph                                                      ##STR139##    167*       7  1 2  2 O       Py2   --     Ph  OCO    Ph  OCOThf    168*       7  1 2  2 O       Py2   --     Ph  OCH.sub.2                                                 Cy                                                      ##STR140##    169*       7  1 2  2 O       Ph    --     Ph  --     Id2                                                      ##STR141##    170*       7  2 2  2 --      Ph    --     Btb1                                          --     --                                                      ##STR142##    171*       7  1 2  4 O       Ph    --     Py1 --     --                                                      ##STR143##    172*       7  1 2  2 O       Py2   --     Id2 --     --                                                      ##STR144##    173*       7  2 3  2 O       Ep2   --     --  --     --                                                      ##STR145##    174*       7  1 3  2 O       Ph    CH.sub.2 O                                      Ph  --     --  OCODp(1)    175*       7  1 3  2 O       Ph    CC     Ph  --     Py1                                                      ##STR146##    176*       7  1 4  2 O       Ph    --     Pr2 --     Ph                                                      ##STR147##    177*       7  1 5  2 --      Ph    --     Pr1 --     --                                                      ##STR148##    178*       7  1 6  2 O       Ph    --     Ph  --     Td                                                      ##STR149##    179*       8  1 1  1 O       Pr2   --     Ph  OCH.sub.2                                                 Cy  OCH.sub.2 La1(5,2)    180*       8  1 1  2 O       Ph    COO    Ph  --     --                                                      ##STR150##    181*       8  1 1  1 --      Ph    --     Pa  --     --                                                      ##STR151##    182*       8  1 1  2 O       Ph    --     Ph  --     --                                                      ##STR152##    183*       8  1 2  2 O       Cy    --     Ph  CH.sub.2 CH.sub.2                                                 Ph  OCH.sub.2 La2(2,0)    184*       8  1 2  2 O       Ph    --     Ph  --     Py1                                                      ##STR153##    185*       8  1 2  3 O       Ph    --     Cy  --     --                                                      ##STR154##    186*       8  1 2  2 O       Cy    --     Ph  OCO    Cy  OCH.sub.2 Lc1(6,6)    187*       8  1 2  2 O       Ph    --     Td  --     --                                                      ##STR155##    188*       8  1 2  2 O       Pr2   --     Ph  OCH.sub.2                                                 Tn                                                      ##STR156##    189*       8  1 3  2 O       Pr1   --     Id2 --     --                                                      ##STR157##    190*       8  1 3  2 O       Ph    --     Cy  --     Ph                                                      ##STR158##    191*       8  1 4  2 O       Ph    --     Py1 --     --  OCH.sub.2 Lc2(3,3)    192*       8  1 4  2 O       Py2   --     Ph  OCH.sub.2                                                 Ph                                                      ##STR159##    193*       8  2 5  2 O       Ph    --     Tz1 --     --                                                      ##STR160##    194*       9  1 1  2 O       Ph    --     Bta1                                          --     --                                                      ##STR161##    195*       9  1 1  2 OCO     Ph    --     Pd  --     Ph                                                      ##STR162##    196*       9  1 2  2 O       Py2   --     Ph  CH.sub.2 CH.sub.2                                                 Id2                                                      ##STR163##    197*       9  1 2  2 O       Ph    --     Pr2 --     Ph                                                      ##STR164##    198*       9  1 2  2 O       Ph    --     Bob2                                          --     Cy  COOLa1(6,0)    199*       9  1 2  2 O       Btb2  --     Ph  --     --                                                      ##STR165##    200*       9  1 3  2 O       Ph    --     Ph  --     --  OCH.sub.2 Thf    201*       9  1 3  2 O       Ph    --     Pr2 --     --                                                      ##STR166##    202*       9  1 4  3 O       Np    --     --  --     --                                                      ##STR167##    203*       9  1 5  2 O       Ph    --     Tn  --     --                                                      ##STR168##    204*       10 1 1  2 O       Cy    --     Ph  OCO    Ph  COOLa1(5,0)    205*       10 1 1  2 --      Ph    --     Tz1 --     Ph                                                      ##STR169##    206*       10 1 2  2 O       Ph    CC     Pd  --     --                                                      ##STR170##    207*       10 2 2  2 O       Ph2M  --     Tz1 --     Ph  OCH.sub.2 Lc2(4;4)    208*       10 1 3  2 O       Ph    --     Py1 --     --                                                      ##STR171##    209*       10 1 4  1 --      Ph    --     Ep1 --     --                                                      ##STR172##    210*       10 1 5  2 OCO     Ph    --     Py2 --     Ph                                                      ##STR173##    211*       11 1 1  2 O       Ph    --     Btb1                                          --     --                                                      ##STR174##    212*       11 1 1  2 O       Ph    --     Ph2CN                                          --     --                                                      ##STR175##    213*       11 1 2  3 O       Ph    COO    Ph  --     --  CH.sub.2 OLc1(6,0)    214*       11 1 2  2 O       Ep2   --     --  --     --                                                      ##STR176##    215*       11 1 2  2 O       Ph    --     Dx1 --     --                                                      ##STR177##    216*       11 1 3  2 O       Ph    --     Pr2 --     --                                                      ##STR178##    217*       12 1 1  2 --      Boa2  --     Ph  --     --  OCH.sub.2 Lc2(3,0)    218*       12 1 1  2 O       Pr2   --     Cm2 --     --                                                      ##STR179##    219*       12 1 2  1 O       Ph    --     Ph  --     --                                                      ##STR180##    220*       12 1 2  2 O       Ph    --     --  --                                                  ##STR181##    221*       12 1 3  2 O       Ph    --     Btb1                                          --     --                                                      ##STR182##    222*       13 1 1  2 O       Gp2   --     --  --     --                                                      ##STR183##    223*       13 1 2  2 O       Ph    --     Py1 --     --                                                      ##STR184##    224*       13 1 2  2 O       Ph    --     Tz1 --     Ph3Br                                                     OCH.sub.2 Pla    225*       13 1 2  2 --      Cy    --     --  --     --                                                      ##STR185##    226*       13 1 2  2 OCO     Cy    --     Ph  OCH.sub.2                                                 Id2                                                      ##STR186##    227*       14 1 2  1 O       Ph    --     Ph2F                                          --     --                                                      ##STR187##    228*       4  1 2  2 O       Ph    --     Py1 --     --  OCH.sub.2 Lc1(0,0)    229*       3  1 2  2 O       Ph    --     Ph  --     --  OCOThf    230*       4  1 2  2 O       Py2   --     Ph  --     --                                                      ##STR188##    231*       3  1 2  2 O       Py2   --     Ph  --     --                                                      ##STR189##    __________________________________________________________________________

The liquid crystal composition according to the present invention may beobtained by mixing at least one species of the mesomorphic compoundrepresented by the formula (I) and at least one species, preferably 1-50species, more preferably 1-30 species, particularly 3-30 species, ofanother mesomorphic compound, in appropriate proportions determined bytaking account of usage or uses of a liquid crystal device using thecomposition, characteristics required therefor, etc.

The liquid crystal composition according to the present invention maypreferably be formulated as a liquid crystal composition capable ofshowing ferroelectricity, particularly a liquid crystal compositionshowing a chiral smectic phase.

Specific examples of another mesomorphic compound described above mayinclude those denoted by the following formulae (III) to (XII).##STR190## wherein e denotes 0 or 1 and f denotes 0 or 1 with provisothat e+f=0 or 1; Y" denotes H, halogen, CH₃ or CF₃ ; and X₁ ' and X₂ 'respectively denote a single bond, ##STR191## X₃ ' and X₄ ' respectivelydenote a single bond, ##STR192##

In the formula (III), preferred compounds thereof may include thoserepresented by the following formulas (IIIa) to (IIIe): ##STR193##wherein g and h respectively denote 0 or 1 with proviso that g+h=0 or 1;i denotes 0 or 1; X₁ ' and X₂ ' respectively denote a single bond,##STR194## and X₃ ', X₄ ' and X₅ ' respectively denote a single bond,##STR195##

In the formula (IV), preferred compounds thereof may include thoserepresented by the following formulas (IVa) to (IVc): ##STR196## whereinj denotes 0 or 1; Y₁ ", Y₂ " and Y₃ " respectively denote H, halogen,CH₃ or CF₃ ; X₁ ' and X₂ ' respectively denote a single bond, ##STR197##and X₃ ' and X₄ ' respectively denote a single bond, ##STR198##

In the formula (V), preferred compounds thereof may include thoserepresented by the following formulas (Va) and (Vb): ##STR199## whereink, l and m respectively denote 0 or 1 with proviso that k+l+m=0, 1 or 2;X₁ ' and X₂ ' respectively denote a single bond, ##STR200## and X₃ ' andX₄ ' respectively denote a single bond, ##STR201##

In the formula (VI), preferred compounds thereof may include thoserepresented by the following formulas (VIa) to (VIf): ##STR202##

Herein, R₁ ' and R₂ ' respectively denote a linear or branched alkylgroup having 1-18 carbon atoms capable of including one ornon-neighboring two or more methylene groups which can be replaced with--CH halogen- and capable of further including one or two or morenon-neighboring methylene groups other than those directly connected toX₁ ' or X₂ ' which can be replaced with at least one species of##STR203## with proviso that R₁ ' and R₂ ' respectively do not connectto a ring structure by a single bond when R₁ ' and R₂ ' respectivelydenote a halogenated alkyl group containing one methylene group replacedwith --CH halogen- or --CH(CF₃)--.

Further, preferred examples of R₁ ' and R₂ ' may respectively includethose represented by the following groups (i) to (ix):

i) a linear alkyl group having 1-15 carbon atoms; ##STR204## wherein pdenotes an integer of 0-5 and q denotes an integer of 2-11 (opticallyactive or inactive); ##STR205## wherein r denotes an integer of 0-6, sdenotes 0 or 1, and t denotes an integer of 1-14 (optically active orinactive); ##STR206## wherein u denotes 0 or 1 and v denotes an integerof 1-16; ##STR207## wherein w denotes an integer of 1-15 (opticallyactive or inactive); ##STR208## wherein x denotes an integer of 0-2 andy denotes an integer of 1-15; ##STR209## wherein z denotes an integer of1-15; ##STR210## wherein A denotes an integer of 0-2 and B denotes aninteger of 1-15 (optically active or inactive); and ##STR211## wherein Cdenotes an integer of 0-2 and D denotes an integer of 1-15 (opticallyactive or inactive).

In the above-mentioned formulas (IIIa) to (IIId), more preferredcompounds thereof may include those represented by the formulas (IIIaa)to (IIIdc): ##STR212##

In the above-mentioned formulas (IVa) to (IVc), more preferred compoundsthereof may include those represented by the formulas (IVaa) to (IVcb):##STR213##

In the above-mentioned formulas (Va) and (Vb), more preferred compoundsthereof may include those represented by the formulas (Vaa) to (Vbf):##STR214##

In the above-mentioned formulas (VIa) to (VIf), more preferred compoundsthereof may include those represented by the formulas (VIaa) to (VIfa):##STR215## wherein E denotes 0 or 1; X₁ ' and X₂ ' respectively denote asingle bond, ##STR216## and X₃ ' denotes a single bond, ##STR217##wherein F and G respectively denote 0 or 1; X₁ ' and X₂ ' respectivelydenote a single bond, ##STR218## and X₃ ' and X₄ ' respectively denote asingle bond, ##STR219##

In the above formula (VII), preferred compounds thereof may includethose represented by the following formulas (VIIa) and (VIIb):##STR220##

In the above formula (VIII), preferred compounds thereof may includethose represented by the following formulas (VIIIa) and (VIIIb).##STR221##

More preferred compounds of the formula (VIIIb) may include thoserepresented by the formulas (VIIIba) to (VIIIbb): ##STR222##

Herein, R₃ ' and R₄ ' respectively denote a linear or branched alkylgroup having 1-18 carbon atoms capable of including one ornon-neighboring two or more methylene groups which can be replaced with--CH halogen- and capable of further including one or two or morenon-neighboring methylene groups other than those directly connected toX₁ ' or X₂ ' which can be replaced with at least one species of##STR223## with proviso that R₃ ' and R₄ ' respectively do not connectto a ring structure by a single bond when R₃ ' and R₄ ' respectivelydenote a halogenated alkyl group containing one methylene group replacedwith --CH halogen-.

Further, preferred examples of R₃ ' and R₄ ' may respectively includethose represented by the following groups (i) to (vii):

i) a linear alkyl group having 1-15 carbon atoms; ##STR224## wherein pdenotes an integer of 0-5 and q denotes an integer of 2-11 (opticallyactive or inactive); ##STR225## wherein r denotes an integer of 0-6, sdenotes 0 or 1, and t denotes an integer of 1-14 (optically active orinactive); ##STR226## wherein u denotes an integer of 0 or 1 and vdenotes an integer of 1-16 (optically active or inactive); ##STR227##wherein w denotes an integer of 1-15 (optically active or inactive);##STR228## wherein A denotes an integer of 0-2 and B denotes an integerof 1-15 (optically active or inactive); and ##STR229## wherein C denotesan integer of 0-2 and D denotes an integer of 1-15 (optically active orinactive). ##STR230## wherein H and J respectively denote 0 or 1 withproviso that H+J=0 or 1; X₁ ' and X₂ ' respectively denote a singlebond, ##STR231## A₂ ' denotes ##STR232## and X₃ ' and X₄ ' respectivelydenote a single bond, ##STR233## wherein X₁ ' and X₂ ' respectivelydenote a single bond, ##STR234## A₃ ' denotes ##STR235## and X₃ ' and X₄' respectively denote a single bond, ##STR236## wherein X₁ ' and X₂ 'respectively denote a single bond, ##STR237## denotes ##STR238## and X₃' respectively denotes a single bond, ##STR239## wherein K, L and Mrespectively denote 0 or 1 with the proviso that K+L+M=0 or 1; X₁ 'denotes a single bond, ##STR240## X₃ ' denotes a single bond, ##STR241##and Y₄ ", Y₅ " and Y₆ " respectively denote H or F.

In the above formula (IX), preferred compounds thereof may include thoserepresented by the following formulas (IXa) to (IXc): ##STR242##

In the above formula (X), preferred compounds thereof may include thoserepresented by the following formulas (Xa) and (Xb): ##STR243##

In the above formula (XII), preferred compounds thereof may includethose represented by the following formulas (XIIa) and (XIId):##STR244##

In the above-mentioned formulas (IXa) to (IXc), more preferred compoundsthereof may include those represented by the formulas (IXaa) to (IXcc):##STR245##

In the above-mentioned formulas (Xa) to (Xb), more preferred compoundsthereof may include those represented by the formulas (Xaa) to (Xbb):##STR246##

In the above formula (XI), preferred compounds thereof may include thoserepresented by the following formulas (XIa) to (XIg): ##STR247##

In the above-mentioned formulas (XIIa) to (XIId), more preferredcompounds thereof may include those represented by the formula (XIIaa)to (XIIdb): ##STR248##

Herein, R₅ ' and R₆ ' respectively denote a linear or branched alkylgroup having 1-18 carbon atoms capable of including one non-neighboringtwo or more methylene groups other than those directly connected to X₁ 'or X₂ ' which can be replaced with at least one species of ##STR249##

Further, preferred examples of R₅ ' and R₆ ' may respectively includethose represented by the following groups (i) to (vi):

i) a linear alkyl group having 1-15 carbon atoms; ##STR250## wherein pdenotes an integer of 0-5 and q denotes an integer of 2-11 (opticallyactive or inactive); ##STR251## wherein r denotes an integer of 0-6, sdenotes 0 or 1, and t denotes an integer of 1-14 (optically active orinactive); ##STR252## wherein w denotes an integer of 1-15 (opticallyactive or inactive); ##STR253## wherein A denotes an integer of 0-2 andB denotes an integer of 1-15 (optically active or inactive); and##STR254## wherein C denotes an integer of 0-2 and D denotes an integerof 1-15 (optically active or inactive).

Specific examples of another mesomorphic compound may also include thoserepresented by the following formulae (XIII) to (XVII). ##STR255##

In the above mesomorphic compounds of the formulae (III) to (XII),(IIIa) to (XIId) and (IIIaa) to (XIIdb), at least one terminal group(i.e., R₁ ' and/or R₂ ', R₃ ' and/or R₄ ', or R₅ ' and/or R₆ ') may bethe group: (CH₂)_(E) C_(G) F_(2G+1) in which E is an integer of 0-10 andG is an integer of 1-15.

In the present invention, mesomorphic compounds represented by thefollowing formulae (XIII) to (XVIII) may also be used as anothermesomorphic compound.

Specific examples of another mesomorphic compound may also include thoserepresented by the following formulae (XIII) to (XVII) includingabbreviations for respective cyclic groups listed below in addition tothose described above. ##STR256##

Herein, R₇ ' and R₈ ' respectively denote hydrogen or a linear orbranched alkyl group having 1-18 carbon atoms capable of including oneor non-neighboring two or more methylene groups which can be replacedwith --O--, --CO--, --CH(CN)-- or --CCH₃ (CN)-- provided thatheteroatoms are not adjacent to each other and capable of including atleast one H which can be replaced with F.

Further, preferred examples of R₇ ' and R₈ ' may respectively includethose represented by the following groups (i) to (viii):

i) a linear alkyl group having 1-15 carbon atoms; ##STR257## wherein pdenotes an integer of 0-5 and q denotes an integer of 2-11 (opticallyactive or inactive); ##STR258## wherein r denotes an integer of 0-6, sdenotes 0 or 1, and t denotes an integer of 1-14 (optically active orinactive); ##STR259## wherein w denotes an integer of 1-15 (opticallyactive or inactive); ##STR260## wherein A denotes an integer of 0-2 andB denotes an integer of 1-15 (optically active or in active); ##STR261##where in C denotes an integer of 0-2 and D denotes an integer of 1-15(optically active or inactive);

vii) .paren open-st.CH₂ .paren close-st._(E) C_(G) F_(2G+1) wherein E isan integer of 0-10 and G is an integer of 1-15; and

viii) H (hydrogen).

In the above formulae (XIII) to (XVIII); N, Q, R and T are 0 or 1; Y₇ ',Y₈ ' and Y₉ ' are H or F; A₄ ' is Ph or Np; and X₇ ' and X₈ 'respectively denote a single bond, --COO--, --OCO--, --CH₂ O-- or --OCH₂--.

The compound of the formula (XIII) may preferably include a compoundrepresented by the following formula (XIIIa):

    R.sub.7 '--(Py2)--(Ph)--OCO--(Tn)--R.sub.8 '               (XIIIa).

The compound of the formula (XVI) may preferably include compoundsrepresented by the following formulae (XVIa) and (XVIb):

    R.sub.7 '--(Tz1)--(Ph)--R.sub.8 '                          (XVIa), and

    R.sub.7 '--(PhY'.sub.7)--(Tz1)--(PhY'.sub.8)--R.sub.8 '    (XVIb).

The compound of the formula (XVII) may preferably include compoundsrepresented by the following formulae (XVIIa) and (XVIIb):

    R.sub.7 '--(Boa2)--(Ph)--O--R.sub.8 '                      (XVIIa), and

    R.sub.7 '--(Boa2)--(Np)--O--R.sub.8 '                      (XVIIb).

The compounds of the formula (XVIII) and may preferably includecompounds represented by the following formulae (XVIIIa) to (XVIIIc):

    R.sub.7 '--(Btb2)--(Ph)--R.sub.8 '                         (XVIIIa),

    R.sub.7 '--(Btb2)--(Ph)--O--R.sub.8 '                      (XVIIIb), and

    R.sub.7 '--(Btb2)--(Np)--O--R.sub.8 '                      (XVIIIc).

The compounds of the formula (XVIa) and (XVIb) may preferably includecompounds represented by the following formulae (XVIa) to (XVIc):

    R.sub.7 '--(Tz1)--(Ph)--O--R.sub.8 '                       (XVIaa),

    R.sub.7 '--(Ph)--(Tz1)--(Ph)--R.sub.8 '                    (XVIba),

    R.sub.7 '--(Ph)--(Tz1)--(Ph)--O--R.sub.8 '                 (XVIbb), and

    R.sub.7 '--(Ph)--(Tz1)--(Ph)--OCO--R.sub.8 '               (XVIbc).

In formulating the liquid crystal composition according to the presentinvention, the liquid crystal composition may desirably contain 1-80 wt.%, preferably 1-60 wt. %, more preferably 1-40 wt. % of a mesomorphiccompound represented by the formula (I) (optically active or inactive).

Further, when two or more species of the mesomorphic compoundsrepresented by the formula (I) are used, the liquid crystal compositionmay desirably contain 1-80 wt. %, preferably 1-60 wt. %, more preferably1-40 wt. %, of the two or more species of the mesomorphic compoundsrepresented by the formula (I) (optically active or inactive).

The liquid crystal device according to the present invention maypreferably be prepared by heating the liquid crystal composition asprepared above into an isotropic liquid under vacuum, filling a blankcell comprising a pair of oppositely spaced electrode plates with thecomposition, gradually cooling the cell to form a liquid crystal layerand restoring the normal pressure.

FIG. 1 is a schematic sectional view of an embodiment of the liquidcrystal device utilizing ferroelectricity as prepared above forexplanation of the structure thereof.

Referring to FIG. 1, the liquid crystal device includes a liquid crystallayer 1 assuming a chiral smectic phase disposed between a pair of glasssubstrates 2 each having thereon a transparent electrode 3 and aninsulating alignment control layer 4. In the present invention, thetransparent electrode 3 may be formed on one of the substrates 2. Theglass substrates 2 are placed or arranged opposite each other. Leadwires 6 are connected to the electrodes so as to apply a driving voltageto the liquid crystal layer 1 from a power supply 7. Outside thesubstrates 2, a pair of polarizers 8 are disposed so as to modulateincident light Io from a light source 9 in cooperation with the liquidcrystal 1 to provide modulated light I.

Each of two glass substrates 2 is coated with a transparent electrode 3comprising a film of In₂ O₃, SnO₂ or ITO (indium-tin-oxide) to form anelectrode plate. Further thereon, an insulating alignment control layer4 is formed by rubbing a film of a polymer such as polyimide with gauzeor acetate fiber-planted cloth so as to uniaxially align the liquidcrystal molecules in the rubbing direction (uniaxial alignmenttreatment). Further, it is also possible to compose the alignmentcontrol layer 4 of two layers, e.g., by first forming an insulatinglayer of an inorganic material, such as silicon nitride, silicon carbidecontaining hydrogen, silicon oxide, boron nitride, boron nitridecontaining hydrogen, cerium oxide, aluminum oxide, zirconium oxide,titanium oxide, or magnesium fluoride, and forming thereon an alignmentcontrol layer of an organic insulating material, such as polyvinylalcohol, polyimide, polyamide-imide, polyester-imide, polyparaxylylene,polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride,polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamineresin, urea resin, acrylic resin, or photoresist resin. Alternatively,it is also possible to use a single layer of inorganic insulatingalignment control layer comprising the above-mentioned inorganicmaterial or organic insulating alignment control layer comprising theabove-mentioned organic material. An inorganic insulating alignmentcontrol layer may be formed by vapor deposition, while an organicinsulating alignment control layer may be formed by applying a solutionof an organic insulating material or a precursor thereof in aconcentration of 0.1 to 20 wt. %, preferably 0.2-10 wt. %, by spinnercoating, dip coating, screen printing, spray coating or roller coating,followed by curing or hardening under prescribed hardening condition(e.g., by heating). The insulating alignment control layer 4 may have athickness of ordinarily 10 Å-1 micron, preferably 10-3000 Å, furtherpreferably 10-1000 Å. The two glass substrates 2 with transparentelectrodes 3 (which may be inclusively referred to herein as "electrodeplates") and further with insulating alignment control layers 4 thereofare held to have a prescribed (but arbitrary) gap with a spacer 5. Forexample, such a cell structure with a prescribed gap may be formed bysandwiching spacers of silica beads or alumina beads having a prescribeddiameter with two glass plates, and then sealing the periphery thereofwith, a sealing material comprising, e.g., an epoxy adhesive.Alternatively, a polymer film or glass fiber may also be used as aspacer. Between the two glass plates, a liquid crystal compositionassuming a chiral smectic phase is sealed up to provide a liquid crystallayer 1 in a thickness of generally 0.5 to 20 μm, preferably 1 to 5 μm.

The transparent electrodes 3 are connected to the external power supply7 through the lead wires 6. Further, outside the glass substrates 2, apair of polarizers 8 arranged in, e.g., right angle cross nicolrelationship are applied. The device shown in FIG. 1 is of atransmission type and accordingly is provided with a light source 9 atthe back of one of the polarizers 8.

FIG. 2 is a schematic illustration of a liquid crystal cell (device)utilizing ferroelectricity for explaining operation thereof. Referencenumerals 21a and 21b denote substrates (glass plates) on which atransparent electrode of, e.g., In₂ O₃, SnO₂, ITO (indium-tin-oxide),etc., is disposed, respectively. A liquid crystal of an SmC*-phase(chiral smectic C phase) or SmH*-phase (chiral smectic H phase) in whichliquid crystal molecular layers 22 are aligned perpendicular to surfacesof the glass plates is hermetically disposed therebetween. Lines 23 showliquid crystal molecules. Each liquid crystal molecule 23 has a dipolemoment (P⊥) 24 in a direction perpendicular to the axis thereof. Theliquid crystal molecules 23 continuously form a helical structure in thedirection of extension of the substrates. When a voltage higher than acertain threshold level is applied between electrodes formed on thesubstrates 21a and 21b, a helical structure of the liquid crystalmolecule 23 is unwound or released to change the alignment direction ofrespective liquid crystal molecules 23 so that the dipole moments (P⊥)24 are all directed in the direction of the electric field. The liquidcrystal molecules 23 have an elongated shape and show refractiveanisotropy between the long axis and the short axis thereof.Accordingly, it is easily understood that when, for instance, polarizersarranged in a cross nicol relationship, i.e., with their polarizingdirections crossing each other, are disposed on the upper and the lowersurfaces of the glass plates, the liquid crystal cell thus arrangedfunctions as a liquid crystal optical modulation device of which opticalcharacteristics vary depending upon the polarity of an applied voltage.

Further, when the liquid crystal cell is made sufficiently thin (e.g.,less than about 10 microns), the helical structure of the liquid crystalmolecules is unwound to provide a non-helical structure even in theabsence of an electric field, whereby the dipole moment assumes eitherof the two states, i.e., Pa in an upper direction 34a or Pb in a lowerdirection 34b as shown in FIG. 3, thus providing a bistable condition.When an electric field Ea or Eb higher than a certain threshold leveland different from each other in polarity as shown in FIG. 3 is appliedto a cell having the above-mentioned characteristics by using voltageapplication means 31a and 31b, the dipole moment is directed either inthe upper direction 34a or in the lower direction 34b depending on thevector of the electric field Ea or Eb. In correspondence with this, theliquid crystal molecules are oriented in either of a first stable state33a and a second stable state 33b.

When the above-mentioned ferroelectric liquid crystal is used as anoptical modulation element, it is possible to obtain two advantages.First is that the response speed is quite fast. Second is that theorientation of the liquid crystal shows bistability. The secondadvantage will be further explained, e.g., with reference to FIG. 3.When the electric field Ea is applied to the liquid crystal molecules,they are oriented in the first stable state 33a. This state is stablyretained even if the electric field is removed. On the other hand, whenthe electric field Eb of which direction is opposite to that of theelectric field Ea is applied thereto, the liquid crystal molecules areoriented to the second stable state 33b, whereby the directions ofmolecules are changed. This state is similarly stably retained even ifthe electric field is removed. Further, as long as the magnitude of theelectric field Ea or Eb being applied is not above a certain thresholdvalue, the liquid crystal molecules are placed in the respectiveorientation states.

FIGS. 5A and 5B are waveform diagrams showing driving voltage waveformsadopted in driving a ferroelectric liquid crystal panel as an embodimentof the liquid crystal device according to the present invention.

Referring to FIG. 5A, at S_(S) is shown a selection scanning signalwaveform applied to a selected scanning line, at S_(N) is shown anon-selection scanning signal waveform applied to a non-selectedscanning line, at I_(S) is shown a selection data signal waveform(providing a black display state) applied to a selected data line, andat I_(N) is shown a non-selection data signal waveform (providing awhite display state) applied to a non-selected data line. Further, at(I_(S) -S_(S)) and (I_(N) -S_(S)) in the figure are shown voltagewaveforms applied to pixels on a selected scanning line, whereby a pixelsupplied with the voltage (I_(S) -S_(S)) assumes a black display stateand a pixel supplied with the voltage (I_(N) -S_(S)) assumes a whitedisplay state. FIG. 5B shows a time-serial waveform used for providing adisplay state as shown in FIG. 6.

In the driving embodiment shown in FIGS. 5A and 5B, a minimum durationΔt of a single polarity voltage applied to a pixel on a selectedscanning line corresponds to the period of a writing phase t₂, and theperiod of a one-line clearing phase t₁ is set to 2Δt.

The parameters V_(S), V_(I) and Δt in the driving waveforms shown inFIGS. 5A and 5B are determined depending on switching characteristics ofa ferroelectric liquid crystal material used. In this embodiment, theparameters are fixed at a constant value of a bias ratio V_(I) /(V_(I)+V_(S))=1/3. It is of course possible to increase a range of a drivingvoltage allowing an appropriate matrix drive by increasing the biasratio. However, a large bias ratio corresponds to a large amplitude of adata signal and leads to an increase in flickering and a lower contrast,thus being undesirable in respect of image quality. According to ourstudy, a bias ratio of about 1/3-1/4 was practical.

The liquid crystal device according to the present invention is used asan element, particularly a display element, for various liquid crystalapparatus.

Based on an arrangement appearing hereinbelow and data format comprisingimage data accompanied with scanning line address data and by adoptingcommunication synchronization using a SYNC signal as shown in FIGS. 7and 8, there is provided a liquid crystal display apparatus of thepresent invention which uses the liquid crystal device according to thepresent invention as a display panel portion.

Referring to FIG. 7, the ferroelectric liquid crystal display apparatus101 includes a graphic controller 102, a display panel 103, a scanningline drive circuit 104, a data line drive circuit 105, a decoder 106, ascanning signal generator 107, a shift resistor 108, a line memory 109,a data signal generator 110, a drive control circuit 111, a graphiccentral processing unit (GCPU) 112, a host central processing unit (hostCPU) 113, and an image data storage memory (VRAM) 114.

Image data are generated in the graphic controller 102 in an apparatusbody and transferred to a display panel 103 by signal transfer means.The graphic controller 102 principally comprises a CPU (centralprocessing unit, hereinafter referred to as "GCPU") 112 and a VRAM(video-RAM, image data storage memory) 114 and is in charge ofmanagement and communication of image data between a host CPU 113 andthe liquid crystal display apparatus (FLCD) 101. The control of thedisplay apparatus is principally performed by the graphic controller102. A light source (not shown) is disposed at the back of the displaypanel 103.

Hereinbelow, the present invention will be explained more specificallywith reference to examples. It is however to be understood that thepresent invention is not restricted to these examples.

In the following examples, the respective symbols denote the followingphase; Iso: isotropic phase; Ch: cholesteric phase; SmA: smectic Aphase; SmC: smectic C phase; Sm3: smectic phase other than SmA and SmC;SmC^(*) : chiral smectic phase; and Cryst.: crystal.

EXAMPLE 1-1

Production of2-hexyl-5-{6-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)naphthalene-2-yl}thiazole(Example Compound No. 68)

(Step 1)

Synthesis of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol

In a 1 liter-reaction vessel, 416 g (3.34M) of 2-chloroethoxyethanol wasplaced. Under cooling on an ice bath, 307.8 g (3.66M) of2,3-dihydro-4H-pyran was added dropwise to the 2-chloroethoxyethanol in10 minutes, followed by stirring for 1 hour at room temperature. Theresultant reaction mixture was subjected to reduced-pressuredistillation to obtain 383 g of 2-chloroethoxyethyl tetrahydropyranylether. Yield: 55.0%, Boiling point (b.p.)=87°-88° C./2 mmHg.

In a 2 liter-reaction vessel, 100 g (0.50M) of2,2,3,3,4,4,4-heptafluorobutanol and 500 ml of ethylene glycol dimethylether were placed. To the mixture, 22 g (0.55M) of 60%-oily sodiumhydride was added in 40 minutes at 10° C. or below, followed by stirringfor 1 hour at the same temperature and stirring for 2.5 hours at roomtemperature. In a 1 liter-autoclave, the reaction mixture and 115.5 g(0.55M) of 2-chloroethoxyethyl tetrahydropyranyl ether were placed andstirred for 8 hours at 170° C. The above reaction was repeated threetimes, whereby 335 g in total of 2-chloroethoxyethyl tetrahydropyranylether was subjected to the reaction, followed by after-treatment of thereaction mixture for three times all together. More specifically, thereaction mixture for three times was poured into water all together andsubjected to extraction with ethyl acetate, followed by washing withwater, drying with anhydrous magnesium sulfate and distilling-off of thesolvent to obtain a residue. The residue was purified by silica gelcolumn chromatography (eluent: n-hexane/isopropyl ether=1/1; 13.2 kg of200 mesh-silica gel) to obtain 17.9 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl tetrahydropyranyl ether(purity: 99% or above) and 354 g of a low-purity product thereof.

Then, 17.4 g (0.047M) of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyltetrahydropyranyl ether (purity: 99% or above), 35 ml of methanol, 18 mlof water and 2.2 ml of concentrated sulfuric acid were placed in a 100ml-reaction vessel, followed by stirring for 2 hours at roomtemperature. The reaction mixture was poured into water and saturatedwith common salt. The saturated reaction mixture was subjected toextraction with ethyl acetate, washed with saturated common salt waterand dried with anhydrous magnesium sulfate, followed by distilling-offof the solvent to obtain a residue. The residue was subjected toreduced-pressure distillation to obtain 6.4 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol (b.p.: 86°-87° C./6 mmHg).

Separately, 354 g of the low-purity product was subjected to the similarreaction as above and subjected three times to reduced-pressuredistillation to obtain 31.7 g of a 99%-purity product.

(Step 2)

Synthesis of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecylp-toluenesulfonate

5.0 g (17.3 mM) of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol and 4.8ml of pyridine were stirred under cooling on an ice bath. To themixture, 4.0 g (20.8 mM) of p-toluenesulfonyl chloride was added,followed by stirring for 3 hours. The reaction mixture was poured intowater and acidified by hydrochloric acid, followed by extraction withethylacetate, washing with water, drying with anhydrous sodium sulfateand distilling-off of the solvent to obtain a residue. The residue waspurified by silica gel column chromatography (eluent: toluene/ethylacetate=10/1) to obtain 7.92 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate (Yield:99.8%).

(Step 3)

Synthesis of2-hexyl-5-{6-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)naphthalene-2-yl}thiazole

0.59 g (2 mM) of 6-hydroxy-2-(2-hexyl-3,6-thiazole-5-yl)naphthalene and0.16 g (2.4 mM) of 85%-potassium hydroxide were dissolved in 1 ml of1-butanol. To the solution, 0.92 g (2 mM) of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate was addedtogether with 1 ml of 1-butanol, followed by heat-refluxing for 4 hours.After the reaction, the reaction mixture was poured into water andacidified by diluted hydrochloric acid, followed by extraction withethyl acetate. The resultant organic layer was washed with water anddried with anhydrous sodium sulfate, followed by distilling-off of thesolvent to obtain a crude product. The crude product was purified bysilica gel column chromatography (eluent: toluene/ethyl acetate=10/2)and recrystallized from methanol to obtain 0.70 g of an objectiveproduct (Yield: 70%).

EXAMPLE 1-2

Production of5-decyl-2-{4-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)phenyl}pyrimidine(Ex. Comp. No. 67)

0.25 g of an objective product was prepared in the same manner as inExample 1-1 except that 1.12 mM of 4-(5-decylpyrimidine-2-yl)phenol wasused instead of 2 mM of6-hydroxy-2-(2-hexyl-1,3-thiazole-5-yl)naphthalene, and that 1.35 mM ofpotassium hydroxide, 3.8 ml of 1-butanol and 1.13 mM of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate were used(Yield: 38.3%).

EXAMPLE 1-3

Production of2-{4-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)phenyl}-5-octylbenzothiazole(Ex. Comp. No. 69)

0.16 g of an objective product was prepared in the same manner as inExample 1-1 except that 0.44 mM of 4-(6-octylbenzothiazole-2-yl)phenolwas used instead of 2 mM of6-hydroxy-2-(2-hexyl-1,3-thiazole-5-yl)naphthalene, and that 0.55 mM ofpotassium hydroxide, 1 ml of dimethylformamide to be used instaed of1-butanol and 0.45 mM of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecylp-toluenesulfonate were used (Yield: 58.2%).

EXAMPLE 1-4

Production of4,4'-bis-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)biphenyl (Ex.Comp. No. 237)

2.3 g of an objective product was prepared in the same manner as inExample 1-1 except that 5.1 mM of biphenyl-4,4'-diol was used instead of2 mM of 6-hydroxy-2-(2-hexyl-1,3-thiazole-5-yl)naphthalene, and that10.2 mM of potassium hydroxide, 30 ml of ethanol to be used instead of1-butanol and 6.8 mM of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecylp-toluenesulfonate were used (Yield: 62%).

The mesomorphic compounds prepared in Examples 1-1 to 1-4 showed thefollowing phase transition series.

    __________________________________________________________________________    (Ex. Comp.                                Phase transition    No.)  Structural Formula                  temperature (°C.)    __________________________________________________________________________    1 (68)          C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2 ) .sub.2O(CH.sub.2 ) .sub.2NpTz2          .sub.6 H.sub.13                                               ##STR262##    2 (67)          C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2 ) .sub.2O(CH.sub.2 ) .sub.2OPhPy          1C.sub.10 H.sub.21                                               ##STR263##    3 (69)          C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2 ) .sub.2O(CH.sub.2 ) .sub.2OPhBt          b1C.sub.8 H.sub.17                                               ##STR264##    4 (237)          C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2 ) .sub.2O(CH.sub.2 ) .sub.2OPhPh          H.sub.2 ) .sub.2O(CH.sub.2 ) .sub.2OCH.sub.2 C.sub.3 F.sub.7                                               ##STR265##    __________________________________________________________________________

EXAMPLE 1-5

A liquid crystal composition 1-A was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula       wt. parts    ______________________________________    C.sub.9 H.sub.19 --Py2--Ph--OC.sub.9 H.sub.19                             6    C.sub.10 H.sub.21 --Py2--Ph--OC.sub.8 H.sub.17                             6    C.sub.8 H.sub.17 O--Pr1--Ph--O (CH.sub.2).sub.5 *CH (CH.sub.3) C.sub.2    H.sub.5                  7    C.sub.11 H.sub.23 O--Py2--Ph--O (CH.sub.2).sub.2 *CH (CH.sub.3) C.sub.2    H.sub.5                  14    C.sub.10 H.sub.21 --Pr2--Ph--C.sub.6 H.sub.13                             8    C.sub.6 H.sub.13 --Py2--Ph--Ph--C.sub.4 H.sub.9                             4    C.sub.8 H.sub.17 --Ph--Pr2--Ph--OC.sub.5 H.sub.11                             2    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             10    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             5    C.sub.10 H.sub.21 O--Ph--COS--Ph--OC.sub.8 H.sub.17                             10    C.sub.6 H.sub.13 --Ph--COO--Ph--Ph--OCH.sub.2 CH (CH.sub.3) C.sub.2    H.sub.5                  7    C.sub.3 H.sub.7 --Cy--CH.sub.2 O--Ph--Py1--C.sub.8 H.sub.17                             7    C.sub.10 H.sub.21 --Ph--Ph--OCH.sub.2 --Ph--C.sub.7 H.sub.15                             5    C.sub.12 H.sub.25 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.5 H.sub.11                             2    C.sub.5 H.sub.11 --Cy--COO--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                             2    C.sub.12 H.sub.25 O--Ph--Pa--COO (CH.sub.2).sub.3 *CH (CH.sub.3) C.sub.2    H.sub.5                  2    C.sub.12 H.sub.25 O--Ph--Pa--O (CH.sub.2).sub.3 *CH (CH.sub.3) OC.sub.3    H.sub.7                  3    ______________________________________

The liquid crystal composition 1-A was further mixed with the followingexample compounds in the indicated proportions to provide a liquidcrystal composition 1-B.

    ______________________________________                                      wt.    Ex. Comp. No.             Structural formula       parts    ______________________________________    3        CF.sub.3 CH.sub.2 O(CH.sub.2).sub.2 OCH.sub.2 --Ph--Py1--C.sub.7             H.sub.15                 3    27       C.sub.2 F.sub.5 CH.sub.2 O(CH.sub.2).sub.2 O (CH.sub.2).sub.4             O--Ph--Pr1--C.sub.11 H.sub.23                                      4             Composition 1-A          93    ______________________________________

Two 0.7 mm-thick glass plates were provided and respectively coated withan ITO film to form an electrode for voltage application, which wasfurther coated with an insulating layer of vapor-deposited SiO₂. On theinsulating layer, a 0.2%-solution of silane coupling agent (KBM-602,available from Shinetsu Kagaku K.K.) in isopropyl alcohol was applied byspinner coating at a speed of 2000 rpm for 15 second and subjected tohot curing treatment at 120° C. for 20 min.

Further, each glass plate provided with an ITO film and treated in theabove described manner was coated with a 1.5%-solution of polyimideresin precursor (SP-510, available from Toray K.K.) indimethylacetoamide by a spinner coater rotating at 2000 rpm for 15seconds. Thereafter, the coating film was subjected to heat curing at300° C. for 60 min. to obtain about 250 Å-thick film. The coating filmwas rubbed with acetate fiber-planted cloth. The thus treated two glassplates were washed with isopropyl alcohol. After silica beads with anaverage particle size of 2.0 microns were dispersed on one of the glassplates, the two glass plates were applied to each other with a bondingsealing agent (Lixon Bond, available from Chisso K.K.) so that theirrubbed directions were parallel to each other and heated at 100° C. for60 min. to form a blank cell.

Then, the liquid crystal composition 1-B prepared above was heated intoan isotropic liquid, and injected into the above prepared cell undervacuum and, after sealing, was gradually cooled to 25° C. at a rate of20° C./hour to prepare a ferroelectric liquid crystal device. The cellgap was found to be about 2 microns as measured by a Berek compensator.

The ferroelectric liquid crystal device was subjected to measurement ofan optical response time (time from voltage application until thetransmittance change reaches 90% of the maximum under the application ofa peak-to-peak voltage Vpp of 20 V in combination with right-anglecross-nicol polarizers) and observation of switching states. In thedevice, a monodomain with a good and uniform alignment characteristicwas observed. The results of the measurement of response time are shownbelow.

    ______________________________________                10° C.                         25° C.                                 40° C.    ______________________________________    Response time (μsec)                  569        307     167    ______________________________________

Comparative Example 1-1

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 1-5 exceptfor injecting the composition 1-A alone used in Example 1-5 into a blankcell, whereby the following results were obtained.

    ______________________________________                10° C.                         25° C.                                 40° C.    ______________________________________    Response time (μsec)                  668        340     182    ______________________________________

EXAMPLE 1-6

A liquid crystal composition 1-C was prepared by mixing the followingExample Compounds instead of those of Example 1-5 in the indicatedproportions with the liquid crystal composition 1-A.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula        wt. parts    __________________________________________________________________________    96     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.2           --Ph--COO--Ph--OCH.sub.2 C.sub.8 H.sub.17                                     2    236    C.sub.3 F.sub.7 (CH.sub.2).sub.2 O(CH.sub.2).sub.4 O           (CH.sub.2).sub.3 --Ph--Btbl--C.sub.6 H.sub.13                                     4           Composition 1-A           94    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-C wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                         25° C.                                 40° C.    ______________________________________    Response time (μsec)                  556        292     161    ______________________________________

EXAMPLE 1-7

A liquid crystal composition 1-D was prepared by mixing the followingExample Compounds instead of those of Example 1-5 in the indicatedproportions with the liquid crystal composition 1-A.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula         wt. parts    __________________________________________________________________________    110    C.sub.5 F.sub.11 (CH.sub.2).sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub           .4 O--Ph--C.tbd.C--Ph--C.sub.10 H.sub.21                                      3    216    C.sub.11 F.sub.23 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.2           O--Ph--Dxl--C.sub.5 H.sub.13                                      3           Composition 1-A            94    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-D wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                         25° C.                                 40° C.    ______________________________________    Response time (μsec)                  572        303     163    ______________________________________

EXAMPLE 1-8

A liquid crystal composition 1-E was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________                                  wt.    Structural formula            parts    ______________________________________    C.sub.7 H.sub.15 --Py2--Ph--OC.sub.9 H.sub.19                                  12    C.sub.11 H.sub.23 --Py2--Ph--OC.sub.6 H.sub.13                                  10    C.sub.8 H.sub.17 --Pr2--Ph--O (CH.sub.2).sub.5 *CH (CH.sub.3) C.sub.2    H.sub.5                       10    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3)                                  3CH.sub.3    C.sub.8 H.sub.17 --Py2--Ph--Ph--OC.sub.6 H.sub.13                                  8    C.sub.6 H.sub.13 O--Ph--OCO--Np--OC.sub.9 H.sub.19                                  4    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                                  6    C.sub.8 H.sub.17 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                                  2    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                                  8    C.sub.10 H.sub.21 O--Ph--COO--Ph--OCH.sub.2 *CH (CH.sub.3) C.sub.2    H.sub.5                       15    C.sub.4 H.sub.9 --Cy--CH.sub.2 O--Ph--Py1--C.sub.6 H.sub.13                                  7    C.sub.5 H.sub.11 --Cy--CH.sub.2 O--Ph--Py1--C.sub.6 H.sub.13                                  7    C.sub.9 H.sub.19 O--Ph--OCH.sub.2 --Ph--Ph--C.sub.7 H.sub.15                                  4    C.sub.6 H.sub.13 *CH(CH.sub.3)O--Ph--COO--Ph--Ph--OCO*CH(CH.sub.3)OC.sub.4     H.sub.9                      2    C.sub.12 H.sub.25 --Py2--Ph--OCO*CH (Cl)*CH (CH.sub.3) C.sub.2 H.sub.5                                  2    ______________________________________

The liquid crystal composition 1-E was further mixed with the followingcompounds in the proportions indicated below to provide a liquid crystalcomposition 1-F.

    __________________________________________________________________________    Ex. Comp. No.           Structural Formula          wt. parts    __________________________________________________________________________    28     C.sub.2 F.sub.5 (CH.sub.2).sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.           2 O--Py2--Ph--OCO--Cy--C.sub.6 H.sub.13                                       2    80     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Pr2--Ph--OCO--Tn--C.sub.4 H.sub.9                                       2    125    C.sub.5 F.sub.11 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.2           O--Ph--Ph--Tzl--C.sub.6 H.sub.13                                       2           Composition 1-E             94    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-F wasused, and the device was subjected to measurement of optical responsetime. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  603         296     159    ______________________________________

Comparative Example 1-2

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 1-5 exceptfor injecting the composition 1-E alone used in Example 1-8 into a blankcell, whereby the following results were obtained.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  784         373     197    ______________________________________

EXAMPLE 1-9

A liquid crystal composition 1-G was prepared by mixing the followingExample Compounds instead of those of Example 1-8 in the indicatedproportions with the liquid crystal composition 1-E.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula         wt. parts    __________________________________________________________________________    39     C.sub.2 F.sub.5 (CH.sub.2).sub.8 O(CH.sub.2).sub.3 O(CH.sub.2).sub.           2 O--Ph--COO--Ph--Tn--C.sub.4 H.sub.9                                      3    85     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Ph--Ph23F--C.sub.6 H.sub.13                                      3    192    C.sub.8 F.sub.17 CH.sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.2           O--Py2--Ph--OCH.sub.2 --Ph--C.sub.5 H.sub.11                                      2           Composition 1-E            92    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-G wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  565         291     157    ______________________________________

EXAMPLE 1-10

A liquid crystal composition 1-H was prepared by mixing the followingExample Compounds instead of those of Example 1-8 in the indicatedproportions with the liquid crystal composition 1-E.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula         wt. parts    __________________________________________________________________________    5      CF.sub.3 (CH.sub.2).sub.4 O (CH.sub.2).sub.2 O(CH.sub.2).sub.4           O--Py2--Ph--OCO--Ph--C.sub.10 H.sub.21                                      2    58     C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Ph--Py2--Ph--C.sub.6 H.sub.13                                      3    99     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.2           O--Ph--Tz1--Ph--C.sub.6 H.sub.13                                      3           Composition 1-E            92    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-H wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  604         313     172    ______________________________________

EXAMPLE 1-11

A liquid crystal composition 1-J was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula       wt. parts    ______________________________________    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.6 H.sub.13                             10    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.9 H.sub.19                             5    C.sub.10 H.sub.21 --Py2--Ph--OCOC.sub.8 H.sub.17                             7    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.3 CH (CH.sub.3) OC.sub.3    H.sub.7                  7    C.sub.12 H.sub.25 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3)                             6CH.sub.3    C.sub.5 H.sub.11 --Py2--Ph--Ph--C.sub.6 H.sub.13                             5    C.sub.7 H.sub.15 --Py2--Ph--Ph--C.sub.6 H.sub.13                             5    C.sub.4 H.sub.9 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             8    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.10 H.sub.21                             8    C.sub.9 H.sub.19 O--Ph--COO--Ph--OC.sub.5 H.sub.11                             20    C.sub.8 H.sub.17 --Ph--COO--Ph--Ph--OCH.sub.2 CH (CH.sub.3) C.sub.2    H.sub.5                  5    C.sub.8 H.sub.17 --Ph--OCO--Ph--Ph--*CH (CH.sub.3) OCOC.sub.6 H.sub.13                             5    C.sub.6 H.sub.13 --Ph--OCH.sub.2 --Ph--Ph--C.sub.7 H.sub.15                             6    C.sub.12 H.sub.25 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                             3    ______________________________________

The liquid crystal composition 1-J was further mixed with the followingcompounds in the proportions indicated below to provide a liquid crystalcomposition 1-K.

    ______________________________________    Ex. Comp.                        wt.    No.    Structural formula        parts    ______________________________________    21     CF.sub.3 CH.sub.2 O(CH.sub.2).sub.8 OCH.sub.2 O--Py2--Cm2--C.sub.6           H.sub.13                  3    71     C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           --Ph--Boa2--C.sub.10 H.sub.21                                     3    93     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.2           O--Ph--Gp2--C.sub.11 H.sub.23                                     3           Composition 1-J           91    ______________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-K wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  460         232     120    ______________________________________

Comparative Example 1-3

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 1-5 exceptfor injecting the composition 1-J alone used in Example 1-11 into thecell, whereby the following results were obtained.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  653         317     159    ______________________________________

EXAMPLE 1-12

A liquid crystal composition 1-L was prepared by mixing the followingExample Compounds instead of those of Example 1-11 in the indicatedproportions with the liquid crystal composition 1-J.

    ______________________________________    Ex.    Comp.                             wt.    No.   Structural formula          parts    ______________________________________    38    C.sub.2 F.sub.5 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.7          OCO--Ph--Ep2--C.sub.6 H.sub.13                                      2    76    C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2).sub.8 O(CH.sub.2).sub.2          O--Ph--Ph--Ph--C.sub.5 H.sub.11                                      4    167   C.sub.7 F.sub.15 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2          O--Py2--Ph--OCO--Ph--F      3          Composition 1-J             91    ______________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-L wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  464         234     121    ______________________________________

EXAMPLE 1-13

A liquid crystal composition 1-M was prepared by mixing the followingExample Compounds instead of those of Example 1-11 in the indicatedproportions with the liquid crystal composition 1-J.

    ______________________________________    Ex. Comp.                         wt.    No.    Structural formula         parts    ______________________________________    147    C.sub.6 F.sub.13 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Np--C.sub.10 H.sub.21   2    169    C.sub.7 F.sub.15 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Ph--Ph--Id2--C.sub.5 H.sub.11                                      2    234    C.sub.3 F.sub.15 CH.sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.2           O--Py2--Ph--C.sub.10 H.sub.21                                      2           Composition 1-J            94    ______________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-5 except that the above liquid crystal composition 1-M wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  474         237     122    ______________________________________

As apparent from the above Examples 1-5 to 1-13, the ferroelectricliquid crystal device including the liquid crystal compositions 1-B,1-C, 1-D, 1-F, 1-G, 1-H, 1-K, 1-L, and 1-M i.e., compositions containinga mesomorphic compound of the formula (I) according to the presentinvention, provided improved operation characteristic at a lowertemperature, high speed responsiveness and a decreased temperaturedependence of response speed.

EXAMPLE 1-14

A blank cell was prepared in the same manner as in Example 1-5 by usinga 2% aqueous solution of polyvinyl alcohol resin (PVA-117, availablefrom Kuraray K.K.) instead of the 1.5%-solution of polyimide resinprecursor in dimethylacetoamide on each electrode plate. A ferroelectricliquid crystal device was prepared by filling the blank cell with theliquid crystal composition 1-B used in Example 1-5. The liquid crystaldevice was subjected to measurement response time in the same manner asin Example 1-5. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  572         308     167    ______________________________________

EXAMPLE 1-15

A blank cell was prepared in the same manner as in Example 1-5 exceptfor omitting the SiO₂ layer to form an alignment control layer composedof the polyimide resin layer alone on each electrode plate. Aferroelectric liquid crystal devices were prepared by filling such ablank cell with liquid crystal composition 1-B used in Example 1-5. Theliquid crystal device was subjected to measurement of response time inthe same manner as in Example 1-5. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  558         298     161    ______________________________________

As is apparent from the above Examples 1-14 and 1-15, also in the caseof a different device structure, the device containing the ferroelectricliquid crystal composition 1-B according to the present inventionprovided an improved low-temperature operation characteristic and adecreased temperature dependence of response speed similarly as inExample 1-5.

EXAMPLE 1-16

A liquid crystal composition 1-N was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula       wt. parts    ______________________________________    C.sub.6 H.sub.13 --Py2--Ph--O (CH.sub.2).sub.4 C.sub.3 F.sub.7                             5    C.sub.11 H.sub.23 --Py2--Ph--OCH.sub.2 C.sub.4 F.sub.9                             10    C.sub.8 H.sub.17 O--Pr1--Ph--O (CH.sub.2).sub.5 CH (CH.sub.3) C.sub.2    H.sub.5                  5    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3)                             10H.sub.3    C.sub.6 H.sub.13 --Py2--Ph--Ph--C.sub.8 H.sub.17                             7    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.6 H.sub.13                             15    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             5    C.sub.4 H.sub.9 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                             5    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                             5    C.sub.12 H.sub.25 O--Ph--Pa--CO (CH.sub.2).sub.3 *CH (CH.sub.3) C.sub.2    H.sub.5                  2    C.sub.10 H.sub.21 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.2 H.sub.5                             5    C.sub.6 H.sub.13 --Cy--COO--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                             2    C.sub.8 H.sub.17 --Ph--OCO--Ph--Ph--CH (CH.sub.3) OCOC.sub.6 H.sub.13                             6    C.sub.8 H.sub.17 --Py2--Ph--OCO--Ph--F                             2    C.sub.7 H.sub.15 O--Ph--Tz1--Ph--C.sub.5 H.sub.11                             3    C.sub.6 H.sub.13 O--Btb2--Ph--OCO (CH.sub.2).sub.6 C.sub.2 F.sub.5                             3    C.sub.8 H.sub.17 O--Ph--COS--Ph--OCH.sub.2 C.sub.3 F.sub.7                             10    ______________________________________

The liquid crystal composition 1-N was further mixed with the followingexample compounds in the indicated proportions to provide a liquidcrystal composition 1-P.

    ______________________________________    Ex. Comp.                         wt.    No.    Structural formula         parts    ______________________________________    43     C.sub.2 F.sub.5 CH.sub.2 O(CH.sub.2).sub.4 OCH.sub.2 --Ph--Tz1--Ph-           -C.sub.6 H.sub.13          3    57     C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Ph--Ph--Cy--C.sub.8 H.sub.17                                      2    236    C.sub.3 F.sub.7 (CH.sub.2).sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.           3 --Ph--Btb1--C.sub.6 H.sub.13                                      3           Composition 1-N            92    ______________________________________

Two 0.7 mm-thick glass plates were provided and respectively coated withan ITO film to form an electrode for voltage application, which wasfurther coated with an insulating layer of vapor-deposited SiO₂. On theinsulating layer, a 0.2%-solution of silane coupling agent (KBM-602,available from Shinetsu Kagaku K.K.) in isopropyl alcohol was applied byspinner coating at a speed of 2000 rpm for 15 second and subjected tohot curing treatment at 120° C. for 20 min.

Further, each glass plate provided with an ITO film and treated in theabove described manner was coated with a 1.0%-solution of polyimideresin precursor (SP-510, available from Toray K.K.) indimethylacetoamide by a spinner coater rotating at 2000 rpm for 15seconds. Thereafter, the coating film was subjected to heat curing at300° C. for 60 min. to obtain about 120 Å-thick film. The coating filmwas rubbed with acetate fiber-planted cloth. The thus treated two glassplates were washed with isopropyl alcohol. After silica beads with anaverage particle size of 1.5 microns were dispersed on one of the glassplates, the two glass plates were applied to each other with a bondingsealing agent (Lixon Bond, available from Chisso K.K.) so that theirrubbed directions were parallel to each other and heated at 100° C. for60 min. to form a blank cell. The cell gap was found to be about 1.5microns as measured by a Berek compensator.

Then, the liquid crystal composition 1-P prepared above was heated intoan isotropic liquid, and injected into the above prepared cell undervacuum and, after sealing, was gradually cooled to 25° C. at a rate of20° C./hour to prepare a ferroelectric liquid crystal device.

The ferroelectric liquid crystal device was subjected to measurement ofa contrast ratio at 30° C. when the device was driven by applying adriving voltage waveform shown in FIGS. 5A and 5B (bias ratio=1/3),whereby a contrast ratio at 30° C. of 19.5 was obtained.

Comparative Example 1-4

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of a contrast ratio in the same manner as in Example 1-16except for injecting the composition 1-N alone used in Example 1-16 intoa blank cell, whereby a contrast ratio of 8.1 was obtained.

EXAMPLE 1-17

A liquid crystal composition 1-Q was prepared by mixing the followingExample Compounds instead of those of Example 1-16 in the indicatedproportions with the liquid crystal composition 1-N.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula            wt. parts    __________________________________________________________________________    40     C.sub.2 F.sub.5 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.3           --Ph--CH.sub.2 O--Ph--OCH(CH.sub.3)CH.sub.2 OC.sub.3 H.sub.7                                         2    89     C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.4           O--Py2--Ph3F--C.sub.6 H.sub.13                                         3    245    C.sub.4 F.sub.9 (CH.sub.2).sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.           2 O--Ph--Py1--(CH.sub.2).sub.5 C.sub.2 F.sub.5                                         3           Composition 1-N               92    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-16 except that the above liquid crystal composition 1-Q wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 21.0 was obtained.

EXAMPLE 1-18

A liquid crystal composition 1-R was prepared by mixing the followingExample Compounds instead of those of Example 1-16 in the indicatedproportions with the liquid crystal composition 1-N.

    ______________________________________    Ex. Comp.                         wt.    No.    Structural formula         parts    ______________________________________    187    C.sub.8 F.sub.17 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Ph--Td--C.sub.9 H.sub.19                                      2    230    C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           O--Py2--Ph--C.sub.8 F.sub.17                                      2    233    C.sub.3 F.sub.7 CH.sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.2           H═CH--Ph--Ph--C.sub.6 H.sub.13                                      2           Composition 1-N            94    ______________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-16 except that the above liquid crystal composition 1-R wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 20.5 was obtained.

EXAMPLE 1-19

A liquid crystal composition 1-S was prepared by mixing the followingExample Compounds instead of those of Example 1-16 in the indicatedproportions with the liquid crystal composition 1-N.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula         wt. parts    __________________________________________________________________________    97     C.sub.4 F.sub.9 CH.sub.2 .sub.2 O(CH.sub.2).sub.4 O(CH.sub.2).sub.2            O--Py2--Np--OCH.sub.2 C.sub.10 F.sub.21                                      2    137    C.sub.5 F.sub.11 CH.sub.2 O(CH.sub.2).sub.7 O(CH.sub.2).sub.4           O--Py2--Id2--C.sub.8 H.sub.17                                      3    242    C.sub.4 F.sub.9 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           --Ph--Py1--O(CH.sub.2).sub.2 O(CH.sub.2).sub.3 C.sub.2 F.sub.5                                      2           Composition 1-N            93    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 1-16 except that the above liquid crystal composition 1-S wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 23.6 was obtained.

As apparent from the above Examples 1-16 to 1-19, the ferroelectricliquid crystal device including the liquid crystal compositions 1-P,1-Q, 1-R and 1-S, i.e., compositions containing a mesomorphic compoundof the formula (I) according to the present invention, provided a highercontrast ratio when driven.

EXAMPLE 1-20

A blank cell was prepared in the same manner as in Example 1-16 by usinga 2% aqueous solution of polyvinyl alcohol resin (PVA-117, availablefrom Kuraray K.K.) instead of the 1.0%-solution of polyimide resinprecursor in dimethylacetoamide on each electrode plate. A ferroelectricliquid crystal device was prepared by filling the blank cell with theliquid crystal composition 1-P used in Example 1-16. The liquid crystaldevice was subjected to measurement a contrast ratio in the same manneras in Example 1-16, whereby a contrast ratio of 23.4 was obtained.

EXAMPLE 1-21

A blank cell was prepared in the same manner as in Example 1-16 exceptfor omitting the SiO₂ layer to form an alignment control layer composedof the polyimide resin layer alone on each electrode plate. Aferroelectric liquid crystal device was prepared by filling such a blankcell with liquid crystal composition 1-P used in Example 1-16. Theliquid crystal device was subjected to measurement of a contrast ratioin the same manner as in Example 1-16, whereby a contrast ratio of 18.6was obtained.

EXAMPLE 1-22

A blank cell was prepared in the same manner as in Example 1-16 exceptthat a 1.0%-solution of polyamide acid (LQ-1802, available from HitachiKasei K.K.) in NMP (N-methylpyrrolidone) was formed instead of the1.0%-solution of polyimide resin precursor in dimethylacetoamide on eachelectrode plate and that the hot curing treatment thereof was effectedat 270° C. for 1 hour. A ferroelectric liquid crystal device wasprepared by filling the blank cell with the liquid crystal composition1-P used in Example 1-16. The liquid crystal device was subjected tomeasurement a contrast ratio in the same manner as in Example 1-16,whereby a contrast ratio of 34.7 was obtained.

As is apparent from the above Examples 1-20, 1-21 and 1-22, also in thecase of a different device structure, the device containing theferroelectric liquid crystal composition 1-P according to the presentinvention provided a higher contrast ratio similarly as in Example 1-16.

Further, when a driving voltage waveform different from that used inExample 1-16, a liquid crystal device using the liquid crystalcomposition according to the present invention provided a highercontrast ratio compared with a liquid crystal device using a liquidcrystal composition containing no mesomorphic compound of the formula(I) of the present invention.

EXAMPLE 2-1

Optically active 5-(4-methylhexyl)-2-4-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)phenyl!pyrimidine (Ex.Comp. No. 54*) was produced through the folloiwng steps 1 to 3.

(Step 1)

Synthesis of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol

In a 1 liter-reaction vessel, 416 g (3.34M) of 2-chloroethoxyethanol wasplaced. Under cooling on an ice bath, 307.8 g (3.66M) of2,3-dihydro-4H-pyran was added dropwise to the 2-chloroethoxyethanol in10 minutes, followed by stirring for 1 hour at room temperature. Theresultant reaction mixture was subjected to reduced-pressuredistillation to obtain 383 g of 2-chloroethoxyethyl tetrahydropyranylether. Yield: 55.0%, Boiling point (b.p.)=87°88° C./2 mmHg.

In a 2 liter-reaction vessel, 100 g (0.50M) of2,2,3,3,4,4,4-heptafluorobutanol and 500 ml of ethylene glycol dimethylether were placed. To the mixture, 22 g (0.55M) of 60%-oily sodiumhydride was added in 40 minutes at 10° C. or below, followed by stirringfor 1 hour at the same temperature and stirring for 2.5 hours at roomtemperature. In a 1 liter-autoclave, the reaction mixture and 115.5 g(0.55M) of 2-chloroethoxyethyl tetrahydropyranyl ether were placed andstirred for 8 hours at 170° C. The above reaction was repeated threetimes, whereby 335 g in total of 2-chloroethoxyethyl tetrahydropyranylether was subjected to the reaction, followed by after-treatment of thereaction mixture for three times all together. More specifically, thereaction mixture for three times was poured into water all together andsubjected to extraction with ethyl acetate, followed by washing withwater, drying with anhydrous magnesium sulfate and distilling-off of thesolvent to obtain a residue. The residue was purified by silica gelcolumn chromatography (eluent: n-hexane/isopropyl ether=1/1; 13.2 kg of200 mesh-silica gel) to obtain 17.4 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl tetrahydropyranyl ether(purity: 99% or above) and 354 g of a low-purity product thereof.

Then, 17.4 g (0.047M) of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyltetrahydropyranyl ether (purity: 99% or above), 35 ml of methanol, 18 mlof water and 2.2 ml of concentrated sulfuric acid were placed in a 100ml-reaction vessel, followed by stirring for 2 hours at roomtemperature. The reaction mixture was poured into water and saturatedwith common salt. The saturated reaction mixture was subjected toextraction with ethyl acetate, washed with saturated common salt waterand dried with anhydrous magnesium sulfate, followed by distilling-offof the solvent to obtain a residue. The residue was subjected toreduced-pressure distillation to obtain 6.4 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol (b.p.: 86°-87° C./6 mmHg).

Separately, 354 g of the low-purity product was subjected to the similarreaction as above and subjected three times to reduced-pressuredistillation to obtain 31.7 g of a 99%-purity product.

(Step 2)

Synthesis of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecylp-toluenesulfonate

5.0 g (17.3 mM) of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecanol and 4.8ml of pyridine were stirred under cooling on an ice bath. To themixture, 4.0 g (20.8 mM) of p-toluenesulfonyl chloride was added,followed by stirring for 3 hours. The reaction mixture was poured intowater and acidified by hydrochloric acid, followed by extraction withethylacetate, washing with water, drying with anhydrous sodium sulfateand distilling-off of the solvent to obtain a residue. The residue waspurified by silica gel column chromatography (eluent: toluene/ethylacetate=10/1) to obtain 7.92 g of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate (Yield:99.8%).

(Step 3)

Synthesis of optically active 5-(4-methylhexyl)-2-4-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)phenyl!pyrimidine

0.3 g (1.11 mM) of optically active5-(4-methylhexyl)-2-(4-hydroxyphenyl)pyrimidine, 0.50 g (1.13 mM) of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate, 0.076 g(1.35 mM) of 85%-KOH and 3.8 ml of butanol were heat-refluxed for 5hours under stirring. After the reaction, the reaction mixture wasplaced in a refrigerator and left standing, followed by filtration. Tothe solid matter on the filter paper, water was added, followed bystirring at room temperature and filtration to obtain an insolublematter on the filter paper. The insoluble matter was dissolved intoluene and dried with anhydrous sodium sulfate, followed by filtrationto obtain a crude product. The crude product was purified by silica gelcolumn chromatography (eluent: toluene/ethyl acetate=50/1) andrecrystallized from methanol to obtain 0.11 g of optically active5-(4-methylhexyl)-2-4-8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)phenyl!pyrimidine(Yield: 18.3%). ##STR266##

EXAMPLE 2-2

Optically active 2-(1-fluoroheptyl)-5-4-(8,8,9,9,10,10,10-heptylfluoro-3,6-dioxadecyloxyphenyl)!-1,3,4-thiadiazole(Ex. Comp. No. 71*) was produced in the following manner.

0.59 g (2.0 mM) of optically active2-(1-fluoroheptyl)-5-(4-hydroxyphenyl)-1,3,4-thiadiazole, 0.92 g (2.0mM) of 8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate,0.16 g of 85%-KOH and 2 ml of butanol were heat-refluxed for 4 hoursunder stirring. After the reaction, the reaction mixture was poured intowater and subjected to extraction with toluene, followed by washing withwater, drying with anhydrous sodium sulfate and distilling-off of thesolvent to obtain a residue. The residue was recrystallized frommethanol and further recrystallized from hexane to obtain 0.17 g ofoptically active 2-(1-fluoroheptyl)-5-4-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxyphenyl)!-1,3,4-thiadiazole(Yield: 17.4%). ##STR267##

EXAMPLE 2-3

Optically active 4-4'-8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxybiphenyl)!tetrahydrofurancarboxylate (Ex. Comp. No. 229*) was produced through the followingsteps 1 and 2.

(Step 1)

Synthesis of4'-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)-4-bisphenol

1.9 g (10.2 mM) of 4,4'-biphenol, 3.0 g (6.8 mM) of8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyl p-toluenesulfonate, 0.54 g(8.2 mM) of 85%-KOH and 30 ml of ethanol were heat-refluxed for 9 hoursunder stirring. After the reaction, the reaction mixture was poured intowater and acidified by hydrochloric acid, followed by extraction withethyl acetate. The extract was washed with water and dried withanhydrous sodium sulfate, followed by distilling-off of the solvent toobtain a residue. To the residue, about 100 ml of chlorofuran was addedand stirred for 10 minutes at room temperature, followed by filtrationto remove an insoluble matter. The filtrate was concentrated to obtain aresidue. The residue was purified by silica gel column chromatography(eluent: toluene/ethyl acetate=10/1) and recrystallized from ethanol toobtain 0.76 g of4'-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)-4-biphenol (Yield:24.5%).

(Step 2)

Synthesis of optically active 4-4'-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxybiphenyl)!tetrahydrofurancarboxylate

0.2 g (0.44 mM) of4'-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxy)-4-biphenol, 0.051 g(0.44 mM) of R-(+)-tetrahydrofuran carboxylic acid, 0.09 g (0.44 mM) ofN,N'-dicyclohexylcarbodiimide, 0.01 g of N,N-dimethylaminopyridine and30 ml of methylene chloride were stirred for 6 hours at roomtemperature. The resultant N,N'-dicyclohexylurea was filtered off andthe filtrate was concentrated to obtain a residue. The residue waspurified by silica gel column chromatography (eluent: toluene/ethylacetate=5/1) and recrystallized from ethanol to obtain 0.2 g ofoptically active 4-4'-(8,8,9,9,10,10,10-heptafluoro-3,6-dioxadecyloxybiphenyl)!tetrahydrofurancarboxylate (Yield: 82.0%) ##STR268##

EXAMPLE 2-4

A liquid crystal composition 2-Z was prepared by mixing the followingcompounds including the Example Compound (Ex. Comp. No. 57*) in theindicated proportions.

    ______________________________________                                  wt.    Structural formula            parts    ______________________________________    C.sub.6 H.sub.13Py2PhOC.sub.12 H.sub.25                                  2.3    C.sub.8 H.sub.17Py2PhOC.sub.9 H.sub.19                                  4.7    C.sub.8 H.sub.17Py2PhOC.sub.10 H.sub.21                                  4.7    C.sub.9 H.sub.19Py2PhOC.sub.8 H.sub.27                                  2.3     ##STR269##                   26.0    C.sub.6 H.sub.13Btb2PhOC.sub.8 H.sub.17                                  20.0    C.sub.5 H.sub.11PhTdPhC.sub.5 H.sub.11                                  5.0    C.sub.6 H.sub.13PhTdPhC.sub.4 H.sub.9                                  5.0    C.sub.11 H.sub.23Py2PhOCOTnC.sub.4 H.sub.9                                  6.7    C.sub.11 H.sub.23Py2Ph3FOCOTnC.sub.4 H.sub.9                                  3.3     ##STR270##                   10.0     ##STR271##                   10.0    ______________________________________

The liquid crystal composition 2-Z showed the following phase transitionseries. ##STR272##

EXAMPLE 2-5

Two 0.7 mm-thick glass plates were provided and respectively coated withan ITO film to form an electrode for voltage application, which wasfurther coated with an insulating layer of vapor-deposited SiO.sub. 2.On the insulating layer, a 0.2%-solution of silane coupling agent(KBM-602, available from Shinetsu Kagaku K.K.) in isopropyl alcohol wasapplied by spinner coating at a speed of 2000 rpm for 15 second andsubjected to hot curing treatment at 120° C. for 20 min.

Further, each glass plate provided with an ITO film and treated in theabove described manner was coated with a 1.5%-solution of polyimideresin precursor (SP-510, available from Toray K.K.) indimethylacetoamide by a spinner coater rotating at 2000 rpm for 15seconds. Thereafter, the coating film was subjected to heat curing at300° C. for 60 min. to obtain about 250 Å-thick film. The coating filmwas rubbed with acetate fiber-planted cloth. The thus treated two glassplates were washed with isopropyl alcohol. After silica beads with anaverage particle size of 2.0 microns were dispersed on one of the glassplates, the two glass plates were applied to each other with a bondingsealing agent (Lixon Bond, available from Chisso K.K.) so that theirrubbed directions were parallel to each other and heated at 100° C. for60 min. to form a blank cell.

Then, the liquid crystal composition 2-Z prepared in Example 2-4 washeated into an isotropic liquid, and injected into the above preparedcell under vacuum and, after sealing, was gradually cooled to 25° C. ata rate of 20° C./hour to prepare a ferroelectric liquid crystal device.The cell gap was found to be about 2 microns as measured by a Berekcompensator.

The ferroelectric liquid crystal device was subjected to measurement ofthe magnitude of spontaneous polarization (Ps) and an optical responsetime (time from voltage application until the transmittance changereaches 90% of the maximum under the application of a peak-to-peakvoltage Vpp of 20 V in combination with right-angle cross-nicolpolarizers). The results of the measurement of response time are shownbelow.

    ______________________________________                10° C.                          20° C.                                  30° C.    ______________________________________    Response time (μsec)                  349         180     119    Ps (nC/cm.sup.2)                  14.6        12.0    9.9    ______________________________________

EXAMPLE 2-6

A liquid crystal composition 2-A was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula        wt. parts    ______________________________________    C.sub.9 H.sub.19 --Py2--Ph--OC.sub.9 H.sub.19                              6    C.sub.10 H.sub.21 --Py2--Ph--OC.sub.8 H.sub.17                              6    C.sub.8 H.sub.17 O--Pr1--Ph--O (CH.sub.2).sub.5 *CH (CH.sub.3) C.sub.2    H.sub.5                   7    C.sub.11 H.sub.23 --Py2--Ph--O (CH.sub.2).sub.2 *CH (CH.sub.3) C.sub.2    H.sub.5                   14    C.sub.10 H.sub.21 --Pr2--Ph--C.sub.6 H.sub.13                              8    C.sub.6 H.sub.13 --Py2--Ph--Ph--C.sub.4 H.sub.9                              4    C.sub.8 H.sub.17 --Ph--Pr2--Ph--OC.sub.5 H.sub.11                              2    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                              10    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                              5    C.sub.10 H.sub.21 O--Ph--COS--Ph--OC.sub.8 H.sub.17                              10    C.sub.6 H.sub.13 --Ph--COO--Ph--Ph--OCH.sub.2 CH (CH.sub.3) C.sub.2    H.sub.5                   7    C.sub.3 H.sub.7 --Cy--CH.sub.2 O--Ph--Py1--C.sub.8 H.sub.17                              7    C.sub.10 H.sub.21 --Ph--Ph--OCH.sub.2 --Ph--C.sub.7 H.sub.15                              5    C.sub.12 H.sub.25 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.5 H.sub.11                              2    C.sub.5 H.sub.11 --Cy--COO--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                              2    C.sub.12 H.sub.25 O--Ph--Pa--COO (CH.sub.2).sub.3 *CH (CH.sub.3) C.sub.2    H.sub.5                   2    C.sub.12 H.sub.25 O--Ph--Pa--O (CH.sub.2).sub.3 *CH (CH.sub.3) OC.sub.3    H.sub.7                   3    ______________________________________

The liquid crystal composition 2-A was further mixed with the followingexample compounds in the indicated proportions to provide a liquidcrystal composition 2-B.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula       wt. parts    __________________________________________________________________________     2*            ##STR273##              2    30*            ##STR274##              2           Composition 2-A          96    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-B wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  407         214     124    ______________________________________

Comparative Example 2-1

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 2-5 exceptfor injecting the composition 2-A prepared in Example 2-6 into a blankcell, whereby the following results were obtained.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  668         340     182    ______________________________________

EXAMPLE 2-7

A liquid crystal composition 2-C was prepared by mixing the followingExample Compounds instead of those of Example 2-6 in the indicatedproportions with the liquid crystal composition 2-A.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula        wt. parts    __________________________________________________________________________    24*            ##STR275##               1    42*            ##STR276##               2           Composition 2-A           97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-C wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  401         211     121    ______________________________________

EXAMPLE 2-8

A liquid crystal composition 2-D was prepared by mixing the followingExample Compounds instead of those of Example 2-6 in the indicatedproportions with the liquid crystal composition 2-A.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula       wt. parts    __________________________________________________________________________     7*    CF.sub.3 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2 OPhCOOPh2FOCO           hf                       1     50*            ##STR277##              1    177*            ##STR278##              2           Composition 2-A          96    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-D wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  391         206     119    ______________________________________

EXAMPLE 2-9

A liquid crystal composition 2-E was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________                                  wt.    Structural formula            parts    ______________________________________    C.sub.7 H.sub.15 --Py2--Ph--OC.sub.9 H.sub.19                                  12    C.sub.11 H.sub.23 --Py2--Ph--OC.sub.6 H.sub.13                                  10    C.sub.8 H.sub.17 --Pr2--Ph--O (CH.sub.2).sub.5 * CH (CH.sub.3) C.sub.2    H.sub.5                       10    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3)                                  3CH.sub.3    C.sub.8 H.sub.17 --Py2--Ph--Ph--OC.sub.6 H.sub.13                                  8    C.sub.6 H.sub.13 O--Ph--OCO--Np--OC.sub.9 H.sub.19                                  4    C.sub.3 H.sub.7 --Cy--COO--Ph--Py--C.sub.11 H.sub.23                                  6    C.sub.8 H.sub.17 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                                  2    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                                  8    C.sub.10 H.sub.21 O--Ph--COO--Ph--OCH.sub.2 *CH (CH.sub.3) C.sub.2    H.sub.5                       15    C.sub.4 H.sub.9 --Cy--CH.sub.2 O--Ph--Py1--C.sub.6 H.sub.13                                  7    C.sub.5 H.sub.11 --Cy--CH.sub.2 O--Ph--Py1--C.sub.6 H.sub.13                                  7    C.sub.9 H.sub.19 O--Ph--OCH.sub.2 --Ph--Ph--C.sub.7 H.sub.15                                  4    C.sub.6 H.sub.13 *CH(CH.sub.3)O--Ph--COO--Ph--Ph--OCO*CH(CH.sub.3)OC.sub.4     H.sub.9                      2    C.sub.12 H.sub.25 --Py2--Ph--OCO*CH (Cl)*CH (CH.sub.3) C.sub.2 H.sub.5                                  2    ______________________________________

The liquid crystal composition 2-E was further mixed with the followingcompounds in the proportions indicated below to provide a liquid crystalcomposition 2-F.

    __________________________________________________________________________    Ex. Comp. No.           Structural Formula          wt. parts    __________________________________________________________________________     27*            ##STR279##                 2    145*   C.sub.6 F.sub.13 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2COOPhG           p2-OCH.sub.2Lc2(1,1)        1           Composition 2-E             97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-F wasused, and the device was subjected to measurement of optical responsetime. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  410         206     116    ______________________________________

Comparative Example 2-2

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 2-5 exceptfor injecting the composition 2-E alone used in Example 2-9 into a blankcell, whereby the following results were obtained.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  784         373     197    ______________________________________

EXAMPLE 2-10

A liquid crystal composition 2-G was prepared by mixing the followingExample Compounds instead of those of Example 2-9 in the indicatedproportions with the liquid crystal composition 2-E.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula       wt. parts    __________________________________________________________________________     6*            ##STR280##              2    172*            ##STR281##              1           Composition 2-E          97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-G wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  457         227     131    ______________________________________

EXAMPLE 2-11

A liquid crystal composition 2-H was prepared by mixing the followingExample Compounds instead of those of Example 2-9 in the indicatedproportions with the liquid crystal composition 2-E.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula          wt. parts    __________________________________________________________________________    174*   C.sub.7 H.sub.15 CH.sub.2 O(CH.sub.2).sub.3 O(CH.sub.2).sub.2           OPhCH.sub.2 OPhOCODp(1)     1    193*            ##STR282##                 1    212*            ##STR283##                 1           Composition 2-E             97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-H wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  443         221     126    ______________________________________

EXAMPLE 2-12

A liquid crystal composition 2-I was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula       wt. parts    ______________________________________    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.6 H.sub.13                             10    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.9 H.sub.19                             5    C.sub.10 H.sub.21 --Py2--Ph OCOC.sub.8 H.sub.17                             7    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.3 CH (CH.sub.3) OC.sub.3    H.sub.7                  7    C.sub.12 H.sub.25 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3) OCH.sub.3                             6    C.sub.5 H.sub.11 --Py2--Ph--Ph--C.sub.6 H.sub.13                             5    C.sub.7 H.sub.15 --Py2--Ph--Ph--C.sub.6 H.sub.13                             5    C.sub.4 H.sub.9 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             8    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.10 H.sub.21                             8    C.sub.9 H.sub.19 O--Ph--COO--Ph--OC.sub.5 H.sub.11                             20    C.sub.8 H.sub.17 --Ph--COO--Ph--Ph--OCH.sub.2 CH (CH.sub.3) C.sub.2    H.sub.5                  5    C.sub.8 H.sub.17 --Ph--OCO--Ph--Ph--*CH (CH.sub.3) OCOC.sub.6 H.sub.13                             5    C.sub.6 H.sub.13 --Ph--OCH.sub.2 --Ph--Ph--C.sub.7 H.sub.15                             6    C.sub.12 H.sub.25 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                             3    ______________________________________

The liquid crystal composition 2-I was further mixed with the followingcompounds in the proportions indicated below to provide a liquid crystalcomposition 2-J.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula           wt. parts    __________________________________________________________________________    35*    C.sub.2 F.sub.5 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           OPhPhOCH.sub.2Thf            2    65*            ##STR284##                  1    75*            ##STR285##                  1           Composition 2-I              96    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-J wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  397         199     105    ______________________________________

Comparative Example 2-3

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of response time in the same manner as in Example 2-5 exceptfor injecting the composition 2-I alone used in Example 2-12 into thecell, whereby the following results were obtained.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  653         317     159    ______________________________________

EXAMPLE 2-13

A liquid crystal composition 2-K was prepared by mixing the followingExample Compounds instead of those of Example 1-12 in the indicatedproportions with the liquid crystal composition 2-I.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula           wt. parts    __________________________________________________________________________    94*            ##STR286##                  1    99*            ##STR287##                  1    114*            ##STR288##                  1           Composition 2-I              97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-K wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  424         212     111    ______________________________________

EXAMPLE 2-14

A liquid crystal composition 2-L was prepared by mixing the followingExample Compounds instead of those of Example 2-12 in the indicatedproportions with the liquid crystal composition 2-I.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula       wt. parts    __________________________________________________________________________    111*            ##STR289##              1    130*            ##STR290##              2           Composition 2-I          97    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-5 except that the above liquid crystal composition 2-L wasused, and the device was subjected to measurement of optical responsetime and observation of switching states. In the device, a monodomainwith a good and uniform alignment characteristic was observed. Theresults of the measurement are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  380         193     101    ______________________________________

As apparent from the above Examples 2-6 to 2-14, the ferroelectricliquid crystal device including the liquid crystal compositions 2-B,2-C, 2-D, 2-F, 2-G, 2-H, 2-J, 2-K, and 2-L i.e., compositions containinga mesomorphic compound of the formula (I) according to the presentinvention, provided improved operation characteristic at a lowertemperature, high speed responsiveness and a decreased temperaturedependence of response speed.

EXAMPLE 2-15

A blank cell was prepared in the same manner as in Example 2-5 by usinga 2% aqueous solution of polyvinyl alcohol resin (PVA-117, availablefrom Kuraray K.K.) instead of the 1.5%-solution of polyimide resinprecursor in dimethylacetoamide on each electrode plate. A ferroelectricliquid crystal device was prepared by filling the blank cell with theliquid crystal composition 2-B used in Example 2-6. The liquid crystaldevice was subjected to measurement response time in the same manner asin Example 2-5. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  405         213     124    ______________________________________

EXAMPLE 2-16

A blank cell was prepared in the same manner as in Example 2-5 exceptfor omitting the SiO₂ layer to form an alignment control layer composedof the polyimide resin layer alone on each electrode plate. Aferroelectric liquid crystal devices were prepared by filling such ablank cell with liquid crystal composition 2-B used in Example 2-6. Theliquid crystal device was subjected to measurement of response time inthe same manner as in Example 2-5. The results are shown below.

    ______________________________________                10° C.                          25° C.                                  40° C.    ______________________________________    Response time (μsec)                  400         202     120    ______________________________________

As is apparent from the above Examples 2-15 and 2-16, also in the caseof a different device structure, the device containing the ferroelectricliquid crystal composition 2-B according to the present inventionprovided an improved low-temperature operation characteristic and adecreased temperature dependence of response speed similarly as inExample 2-6.

EXAMPLE 2-17

A liquid crystal composition 2-M was prepared by mixing the followingcompounds in the indicated proportions.

    ______________________________________    Structural formula       wt. parts    ______________________________________    C.sub.6 H.sub.13 --Py2--Ph--O (CH.sub.2).sub.4 C.sub.3 F.sub.7                             5    C.sub.11 H.sub.23 --Py2--Ph--OCH.sub.2 C.sub.4 F.sub.9                             10    C.sub.8 H.sub.17 O--Pr1--Ph--O (CH.sub.2).sub.5 CH (CH.sub.3) C.sub.2    H.sub.5                  5    C.sub.10 H.sub.21 --Py2--Ph--O (CH.sub.2).sub.4 CH (CH.sub.3)                             10H.sub.3    C.sub.6 H.sub.13 --Py2--Ph--Ph--C.sub.8 H.sub.17                             7    C.sub.8 H.sub.17 --Py2--Ph--OC.sub.6 H.sub.13                             15    C.sub.5 H.sub.11 --Cy--COO--Ph--Py1--C.sub.12 H.sub.25                             5    C.sub.4 H.sub.9 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                             5    C.sub.3 H.sub.7 --Cy--COO--Ph--Py1--C.sub.11 H.sub.23                             5    C.sub.12 H.sub.25 O--Ph--Pa--CO (CH.sub.2).sub.3 *CH (CH.sub.3) C.sub.2    H.sub.5                  2    C.sub.10 H.sub.21 --Py2--Ph--OCH.sub.2 *CH (F) C.sub.2 H.sub.5                             5    C.sub.6 H.sub.13 --Cy--COO--Ph--OCH.sub.2 *CH (F) C.sub.6 H.sub.13                             2    C.sub.8 H.sub.17 --Ph--OCO--Ph--Ph--CH (CH.sub.3) OCOC.sub.6 H.sub.13                             6    C.sub.8 H.sub.17 --Py2--Ph--OCO--Ph--F                             2    C.sub.7 H.sub.15 O--Ph--Tzl--Ph--C.sub.5 H.sub.11                             3    C.sub.6 H.sub.13 O--Btb2--Ph--OCO (CH.sub.2).sub.6 C.sub.2 F.sub.5                             3    C.sub.8 H.sub.17 O--Ph--COS--Ph--OCH.sub.2 C.sub.3 F.sub.7                             10    ______________________________________

The liquid crystal composition 2-M was further mixed with the followingexample compounds in the indicated proportions to provide a liquidcrystal composition 2-N.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula             wt. parts    __________________________________________________________________________     83*            ##STR291##                    1    118*   C.sub.5 F.sub.11 CH.sub.2 O(CH.sub.2).sub.2 O(CH.sub.2).sub.2           OPhPr1-OCH.sub.2Lc1(2,2)       1    142*            ##STR292##                    1           Composition 2-M                97    __________________________________________________________________________

Two 0.7 mm-thick glass plates were provided and respectively coated withan ITO film to form an electrode for voltage application, which wasfurther coated with an insulating layer of vapor-deposited SiO₂. On theinsulating layer, a 0.2%-solution of silane coupling agent (KBM-602,available from Shinetsu Kagaku K.K.) in isopropyl alcohol was applied byspinner coating at a speed of 2000 rpm for 15 second and subjected tohot curing treatment at 120° C. for 20 min.

Further, each glass plate provided with an ITO film and treated in theabove described manner was coated with a 1.0%-solution of polyimideresin precursor (SP-510, available from Toray K.K.) indimethylacetoamide by a spinner coater rotating at 2000 rpm for 15seconds. Thereafter, the coating film was subjected to heat curing at300° C. for 60 min. to obtain about 120 Å-thick film. The coating filmwas rubbed with acetate fiber-planted cloth. The thus treated two glassplates were washed with isopropyl alcohol. After silica beads with anaverage particle size of 1.5 microns were dispersed on one of the glassplates, the two glass plates were applied to each other with a bondingsealing agent (Lixon Bond, available from Chisso K.K.) so that theirrubbed directions were parallel to each other and heated at 100° C. for60 min. to form a blank cell. The cell gap was found to be about 1.5microns as measured by a Berek compensator.

Then, the liquid crystal composition 2-N prepared above was heated intoan isotropic liquid, and injected into the above prepared cell undervacuum and, after sealing, was gradually cooled to 25° C. at a rate of20° C./hour to prepare a ferroelectric liquid crystal device.

The ferroelectric liquid crystal device was subjected to measurement ofa contrast ratio at 30° C. when the device was driven by applying adriving voltage waveform shown in FIGS. 5A and 5B (bias ratio=1/3),whereby a contrast ratio at 30° C. of 20.1 was obtained.

Comparative Example 2-4

A ferroelectric liquid crystal device was prepared and subjected tomeasurement of a contrast ratio in the same manner as in Example 2-17except for injecting the composition 2-M alone used in Example 2-17 intoa blank cell, whereby a contrast ratio of 8.1 was obtained.

EXAMPLE 2-18

A liquid crystal composition 2-O was prepared by mixing the followingExample Compounds instead of those of Example 2-17 in the indicatedproportions with the liquid crystal composition 2-M.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula             wt. parts    __________________________________________________________________________    165*            ##STR293##                    2    189*            ##STR294##                    3           Composition 2-M                95    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-17 except that the above liquid crystal composition 2-O wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 25.2 was obtained.

EXAMPLE 2-19

A liquid crystal composition 2-P was prepared by mixing the followingExample Compounds instead of those of Example 2-17 in the indicatedproportions with the liquid crystal composition 2-M.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula           wt. parts    __________________________________________________________________________    112*            ##STR295##                  1    127*            ##STR296##                  2    155*            ##STR297##                  1           Composition 2-M              96    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-17 except that the above liquid crystal composition 2-P wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 23.4 was obtained.

EXAMPLE 2-20

A liquid crystal composition 2-Q was prepared by mixing the followingExample Compounds instead of those of Example 2-17 in the indicatedproportions with the liquid crystal composition 2-M.

    __________________________________________________________________________    Ex. Comp. No.           Structural formula           wt. parts    __________________________________________________________________________    119*            ##STR298##                  1    206*            ##STR299##                  2    223*            ##STR300##                  1           Composition 2-M              96    __________________________________________________________________________

A ferroelectric liquid crystal device was prepared in the same manner asin Example 2-17 except that the above liquid crystal composition 2-Q wasused, and the device was subjected to measurement of a contrast ratio,whereby a contrast ratio of 24.8 was obtained.

As apparent from the above Examples 2-17 to 2-20, the ferroelectricliquid crystal device including the liquid crystal compositions 2-N,2-O, 2-P and 2-Q, i.e., compositions containing a mesomorphic compoundof the formula (I) according to the present invention, provided a highercontrast ratio when driven.

EXAMPLE 2-21

A blank cell was prepared in the same manner as in Example 2-17 by usinga 2% aqueous solution of polyvinyl alcohol resin (PVA-117, availablefrom Kuraray K.K.) instead of the 1.0%-solution of polyimide resinprecursor in dimethylacetoamide on each electrode plate. A ferroelectricliquid crystal device was prepared by filling the blank cell with theliquid crystal composition 2-N used in Example 2-17. The liquid crystaldevice was subjected to measurement a contrast ratio in the same manneras in Example 2-17, whereby a contrast ratio of 23.9 was obtained.

EXAMPLE 2-22

A blank cell was prepared in the same manner as in Example 2-17 exceptfor omitting the SiO₂ layer to form an alignment control layer composedof the polyimide resin layer alone on each electrode plate. Aferroelectric liquid crystal device was prepared by filling such a blankcell with liquid crystal composition 2-N used in Example 2-17. Theliquid crystal device was subjected to measurement of a contrast ratioin the same manner as in Example 2-17, whereby a contrast ratio of 19.4was obtained.

EXAMPLE 2-23

A blank cell was prepared in the same manner as in Example 2-17 exceptthat a 1.0%-solution of polyamide acid (LQ-1802, available from HitachiKasei K.K.) in NMP (N-methylpyrrolidone) was formed instead of the1.0%-solution of polyimide resin precursor in dimethylacetoamide on eachelectrode plate and that the hot curing treatment thereof was effectedat 270° C. for 1 hour. A ferroelectric liquid crystal device wasprepared by filling the blank cell with the liquid crystal composition2-N used in Example 2-17. The liquid crystal device was subjected tomeasurement a contrast ratio in the same manner as in Example 2-17,whereby a contrast ratio of 34.6 was obtained.

As is apparent from the above Examples 2-21, 2-22 and 2-23, also in thecase of a different device structure, the device containing theferroelectric liquid crystal composition 2-N according to the presentinvention provided a higher contrast ratio similarly as in Example 2-17.

Further, when a driving voltage waveform different from that used inExample 2-17, a liquid crystal device using the liquid crystalcomposition according to the present invention provided a highercontrast ratio compared with a liquid crystal device using a liquidcrystal composition containing no mesomorphic compound of the formula(I) of the present invention.

As described hereinabove, according to the present invention, byutilizing a ferroelectricity exhibited by a liquid crystal compositioncontaining at least one mesomorphic compound of the formula (I), thereis provided a liquid crystal device providing improved characteristicsuch as a good alignment characteristic, a good switching property,high-speed responsiveness, a decreased temperature-dependence ofresponse speed, a high contrast ratio, and a stable layer structure ofliquid crystal molecules.

In addition, when the liquid crystal device is used as a display devicein combination with a light source, drive circuit, etc., a liquidcrystal apparatus, such as a liquid crystal display apparatus, providinggood display characteristics can be realized.

What is claimed is:
 1. An optically inactive mesomorphic compoundrepresented by the following formula (I):

    C.sub.m F.sub.2m+1 (CH.sub.2).sub.n O(CH.sub.2).sub.p O(CH.sub.2).sub.q --Y.sub.1 --A.sub.1 --R.sub.1                             (I),

wherein R₁ denotes H, halogen, CN or a linear, branched or cyclizedalkyl group having 1-30 carbon atoms capable of including at least one--CH₂ -- group which can be replaced with --O--, --S--, --CO--,--CH(Cl)--, --CH(CN)--, --CCH₃ (CN)--, --CH═CH-- or --C═CH-- or--C.tbd.C-- provided that heteroatoms are not adjacent to each other andcapable of including at least one H which can be replaced with F; m, n,p and q independently denote an integer of 1-15 provided thatm+n+p+q≦18; Y₁ denotes a single bond, --O--, --CO--, --COO--, --OCO--,--CH═CH-- or --C.tbd.C--; and A₁ denotes --A₂ --, --A₂ --X₁ --A₃ -- or--A₂ --X₁ --A₃ --X₂ --A₄ -- in which A₂, A₃ and A₄ independently denotea divalent cyclic group selected from the group consisting of1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; pyridine-2,5-diyl; pyrimidine-2,5-diyl;pyrazine-2,5-diyl: pyridazine-3,6-diyl; 1,4-cyclohexylene;1,3-dioxane-2,5-diyl; 1,3-dithiane-2,5-diyl; thiophene-2,5-diyl;thiazole-2,5-diyl; thiadiazole-2,5-diyl; benzoxazole-2,5-diyl;benzoxazole-2,6-diyl; benzothiazole-2,5-diyl; benzothiazole-2,6-diyl;quinoxaline-2,6-diyl; quinoline-2,6-diyl; 2,6-naphthylene;indan-2,5-diyl; 2-alkylindan-2,5-diyl having a linear or branched C₁₋₁₈alkyl group; indanone-2,6-diyl; 2-alkylindanone-2,6-diyl having a linearor branched C₁₋₁₈ alkyl group; coumaran-2,5-diyl; and2-alkylcumaran-2,5-diyl having a linear or branched C₁₋₁₈ alkyl group;and X₁ and X₂ independently denote a single bond, --COO--, --OCO--,--CH₂ O--, --OCH₂ --, --CH₂ CH₂ --, --CH═CH-- or --C.tbd.C--, whereinatleast one of A₂ and A₃ is a divalent cyclic group selected from thegroup consisting of thiophene-2,5-diyl; thiazole-2,5-diyl;thiadiazole-2,5-diyl; benzoxazole-2,5-diyl; benzoxazole-2,6-diyl;benzothiazole-2,5-diyl; benzothiazole-2,6-diyl; quinoxaline-2,6-diyl;quinoline-2,6-diyl; indan-2,5-diyl; 2-alkylindan-2,5-diyl having alinear or branched C₁₋₁₈ alkyl group; indanone-2,6-diyl;2-alkylindanone-2,6-diyl having a linear or branched C₁₋₁₈ alkyl group;coumaran-2,5-diyl; and 2-alkylcumaran-2,5-diyl having a linear orbranched C₁₋₁₈ alkyl group.
 2. A compound according to claim 1, whereinR₁ in the formula (I) is H, halogen, CN, or a linear, branched orcyclized alkyl group having 1-20 carbon atoms capable of including atleast one --CH₂ -- group which can be replaced with --O--, --S--,--CO--, --CH(CN)--, --CH═CH-- or --C.tbd.C-- provided that heteroatomsare not adjacent to each other and capable of including at least one Hwhich can be replaced with F.
 3. A compound according to claim 1, whichis any one of the following mesomorphic compounds (Ia) to (Ic) of theformula (I):Compound (Ia) wherein A₁ is --A₂ -- and A₂ is a divalentcyclic group selected from the group consisting of quinoxaline-2,6-diyland quinoline-2,6-diyl; Compound (Ib) wherein A₁ is --A₂ --X₁ --A₃ -- inwhich one of A₂ and A₃ is a divalent cyclic group independently selectedfrom the group consisting of 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; 1,4-cyclohexylene;pyridine-2,5-diyl; and pyrimidine-2,5-diyl; and Compound (Ic) wherein A₁is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one or two of A₂, A₃ and A₄other than a combination of A₂ and A₃ is 1,4-phenylene capable of havingone or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN and theremaining groups of A₂, A₃ and A₄ is a divalent group independentlyselected from the group consisting of thiazole-2,5-diyl;thiadiazole-2,5-diyl; indan-2,5-diyl; and coumaran-2,5-diyl.
 4. Acompound according to claim 1, which is any one of the followingmesomorphic compounds (Ibb) to (Ice) of the formula (I):Compound (Ibb)wherein A₁ is --A₂ --X₁ --A₃ -- in which one of the groups A₂ and A₃ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; the other group A₂ or A₃ is a divalent cyclicgroup selected from the group consisting of thiophene-2,5-diyl,thiazole-2,5-diyl, thiadiazole-2,5-diyl, benzoxazole-2,5-diyl,benzothiazole-2,6-diyl, quinoxaline-2,6-diyl, quinoline-2,6-diyl,indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond; Compound(Ibc) wherein A₁ is --A₂ --X₁ --A₃ -- in which one of the groups A₂ andA₃ is pyridine-2,5-diyl; the other group A₂ or A₃ is a divalent cyclicgroup selected from the group consisting of indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond; Compound (Ibd) wherein A₁ is--A₂ --X₁ --A₃ -- in which one of the groups A₂ and A₃ ispyrimidine-2,5-diyl; the other group A₂ or A₃ is a divalent cyclic groupselected from the group consisting of indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond; Compound (Icb) wherein A₁ is--A₂ --X₁ --A₃ --X₂ --A₄ -- in which A₂ and A₄, or A₃ and A₄ are1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and the remaining group A₂ or A₃ is a divalentcyclic group selected from the group consisting of thiazole-2,5-diyl,thiadiazole-2,5-diyl, indan-2,5-diyl and coumaran-2,5-diyl; and X₁ andX₂ are a single bond; Compound (Icc) wherein A₁ is --A₂ --X₁ --A₃ --X₂--A₄ -- in which A₄ is pyridine-2,5-diyl; A₂ is a divalent cyclic groupselected from the group consisting of thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and one of the groupsX₁ and X₂ is a single bond and the other group X₁ or X₂ is --OCO--,--OCH₂ -- or --CH₂ CH₂ --; Compound (Icd) wherein A₁ is --A₂ --X₁ --A₃--X₂ --A₄ -- in which A₄ is pyrimidine-2,5-diyl; A₂ is a divalent cyclicgroup selected from the group consisting of thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and one of the groupsX₁ and X₂ is a single bond and the other group X₁ or X₂ is --OCO--,--OCH₂ -- or --CH₂ CH₂ --; and Compound (Ice) wherein A₁ is --A₂ --X₁--A₃ --X₂ --A₄ -- in which A₄ is 1,4-cyclohexylene; A₂ is a divalentcyclic group selected from the group consisting of thiophene-2,5-diyl,and indan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and one of the groupsX₁ and X₂ is a single bond and the other group X₁ or X₂ is --OCO--,--OCH₂ -- or --CH₂ CH₂ --.
 5. A compound according to claim 1, which isany one of the following mesomorphic compounds (Ibba) to (Ibda) of theformula (I);Compound (Ibba) wherein A₁ is --A₂ --X₁ --A₃ -- in which A₂is 1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; A₃ is a divalent cyclic group selected from thegroup consisting of thiophene-2,5-diyl, thiazole-2,5-diyl,thiadiazole-2,5-diyl, benzoxazole-2,5-diyl, benzothiazole-2,6-diyl,quinoxaline-2,6-diyl, quinoline-2,6-diyl, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond; Compound (Ibca) wherein A₁is --A₂ --X₁ --A₃ -- in which A₂ is pyridine-2,5-diyl; A₃ is a divalentcyclic group selected from the group consisting of indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond; Compound (Ibda) wherein A₁is --A₂ --X₁ --A₃ -- in which A₂ is pyrimidine-2,5-diyl; A₃ is adivalent cyclic group selected from the group consisting ofindan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond.
 6. Acompound according to claim 1, wherein m is an integer of 1-12 and n andp each are integer of 1-5 provided that m+n+p+q≦15; and R₁ in theformula (I) is any one of the following groups (i) to (vii): ##STR301##in which a is an integer of 1-16; m' is an integer of 1-12; n', p' andq' each are an integer of 1-5; d, g and i each are an integer of 0-7; b,e and h each are an integer of 1-10; f is 0 or 1 with the proviso thatm'+n'+p'+q'≦15, b+d≦16, e+f+g≦16, and h+i≦16, and Y₁ ' is a single bond,--O--, --COO-- or --OCO--.
 7. An optically active mesomorphic compoundrepresented by the following formula (I):

    C.sub.m F.sub.2m+1 (CH.sub.2).sub.n O(CH.sub.2).sub.p O(CH.sub.2).sub.q --Y.sub.1 --A.sub.1 --R.sub.1                             (I),

wherein R₁ is a linear, branched or cyclized alkyl group having 2-30carbon atoms capable of including at least one --CH₂ -- group which canbe replaced with --O--, --S--, --CH(Cl)--, --CH(CN)--, --CCH₃ (CN)--,--CH═CH-- or --C.tbd.C-- provided that heteroatoms are not adjacent toeach other and capable of including at least one H which can be replacedwith F, m, n, p and q independently denote an integer of 1-15 providedthat m+n+p+q≦18; Y₁ denotes a single bond, --O--, --CO--, --COO--,--OCO--, --CH═CH-- or --C.tbd.C--; and A₁ denotes --A₂ --, --A₂ --X₁--A₃ -- or --A₂ --X₁ --A₃ --X₂ --A₄ in which A₂, A₃ and A₄ independentlydenote a divalent cyclic group selected from the group consisting of1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; pyridine-2,5-diyl; pyrimidine-2,5-diyl;pyrazine-2,5-diyl; pyridazine-3,6-diyl; 1,4-cyclohexylene;1,3-dioxane-2,5-diyl; 1,3-dithiane-2,5-diyl; thiophene-2,5-diyl;thiazole-2,5-diyl; thiadiazole-2,5-diyl; benzoxazole-2,5-diyl;benzoxazole-2,6-diyl; benzothiazole-2,5-diyl; benzothiazole-2,6-diyl;quinoxaline-2,6-diyl; quinoline-2,6-diyl; 2,6-naphthylene;indan-2,5-diyl; 2-alkylindan-2,5-diyl having a linear or branched C₁₋₁₈alkyl group; indanone-2,6-diyl; 2-alkylindanone-2,6-diyl having a linearor branched C₁₋₁₈ alkyl group; coumaran-2,5-diyl; and2-alkylcumaran-2,5-diyl having a linear or branched C₁₋₁₈ alkyl group;and X₁ and X₂ independently denote a single bond, --COO--, --OCO--,--CH₂ O--, --OCH₂ --, --CH₂ CH₂ --, --CH═CH-- or --C.tbd.C--, whereinatleast one of A₂, A₃ and A₄ is 1,4-cyclohexylene, a heterocyclic ringgroup or a condensed ring group when A₁ is --A₂ --X₁ --A₃ --X₂ --A₄. 8.A compound according to claim 7, wherein formula (I) is any one of thefollowing mesomorphic compounds (Ia), (Ib) or (Ic):Compound (Ia) whereinA₁ is --A₂ -- and A₂ is a divalent cyclic group selected from the groupconsisting of 1,4-phenylene capable of having one or two substituentscomprising F, Cl, Br, CH₃, CF₃ or CN; 1,4-cyclohexylene;quinoxaline-2,6-diyl; quinoline-2,6-diyl; and 2,6-naphthylene; Compound(Ib) wherein A₁ is --A₂ --X₁ --A₃ -- in which at least one of A₂ and A₃is a divalent cyclic group selected from the group consisting of1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; 1,4-cyclohexylene; pyridine-2,5-diyl; andpyrimidine-2,5-diyl; and Compound (Ic) wherein A₁ is --A₂ --X₁ --A₃ --X₂--A₄ -- in which at least one of A₂, A₃ and A₄ is 1,4-phenylene capableof having one or two substituents comprising F, Cl, Br, CH₃, CF₃ or CNand the remainder of A₂, A₃ and A₄ is a divalent group selected from thegroup consisting of 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; pyridine-2,5-diyl;pyrimidine-2,5-diyl; 1,4-cyclohexylene; thiazole-2,5-diyl;thiadiazole-2,5-diyl; indan-2,5-diyl; and coumaran-2,5-diyl.
 9. Acompound according to claim 7, wherein formula (I) is any one of thefollowing mesomorphic compounds (Iba), (Ibb), (Ibc), (Ibd), (Icb),(Icc), (Icd) or (Ice);Compounds (Iba) wherein A₁ is --A₂ --X₁ --A₃ -- inwhich each of A₂ and A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and X₁ is a singlebond, --COO--, --CH₂ O--, --CH₂ CH₂ -- or --C.tbd.C--; Compound (Ibb)wherein A₁ is --A₂ --X₁ --A₃ -- in which one of the groups A₂ and A₃ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; the other group A₂ or A₃ is a divalent cyclicgroup selected from the group consisting of pyridine-2,5-diyl,pyrimidine-2,5-diyl, pyrazine-2,5-diyl, pyridazine-3,6-diyl,1,4-cyclohexylene, thiophene-2,5-diyl, thiazole-2,5-diyl,thiadiazole-2,5-diyl, benzoxazole-2,5-diyl, benzothiazole-2,6-diyl,quinoxaline-2,6-diyl, quinoline-2,6-diyl, 2,6-naphthylene,indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is a single bond; Compound(Ibc) wherein A₁ is --A₂ --X₁ --A₃ -- in which one of the groups A₂ andA₃ is pyridine-2,5-diyl; the other group A₂ or A₃ is a divalent cyclicgroup selected from the group consisting of 1,4-cyclohexylene,2,6-naphthylene, indan-2,5-diyl and coumaran-2,5-diyl; and X₁ is asingle bond; Compound (Ibd) wherein A₁ is --A₂ --X₁ --A₃ -- in whicheach one of the groups A₂ and A₃ is pyrimidine-2,5-diyl; the other groupA₂ or A₃ is a divalent cyclic group selected from the group consistingof 1,4-cyclohexylene, 2,6-naphthylene, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ is a single bond; Compound (Icb) wherein A₁ is--A₂ --X₁ --A₃ --X₂ --A₄ -- in which two of A₂, A₃ and A₄ is1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃, or CN; and the remainder of A₂, A₃ and A₄ is adivalent cyclic group selected from the group consisting ofpyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,4-cyclohexylene,thiazole-2,5-diyl, thiadiazole-2,5-diyl, indan-2,5-diyl andcoumaran-2,5-diyl; and X₁ and X₂ are a single bond; Compound (Icc)wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one of the groups A₂and A₄ is pyridine-2,5-diyl and the other group A₂ or A₄ is a divalentcyclic group selected from the group consisting of 1,4-phenylene capableof having one or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN,1,4-cyclohexylene, thiophene-2,5-diyl, and indan-2,5-diyl; A₃ is a1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and one of the groups X₁ and X₂ is a single bondand the other group X₁ or X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --;Compound (Icd) wherein A₁ is --A₂ --X₁ --A₃ --X₂ --A₄ -- in which one ofthe groups A₂ and A₄ is pyrimidine-2,5-diyl and the other group A₂ or A₄is a divalent cyclic group selected from the group consisting of1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN, 1,4-cyclohexylene, thiophene-2,5-diyl, andindan-2,5-diyl; A₃ is 1,4-phenylene capable of having one or twosubstituents comprising F, Cl, Br, CH₃, CF₃ or CN; and one of the groupsX₁ and X₂ is a single bond and the other group X₁ or X₂ is --OCO--,--OCH₂ -- or --CH₂ CH₂ --; and Compound (Ice) wherein A₁ is --A₂ --X₁--A₃ --X₂ --A₄ -- in which one of the groups A₂ and A₄ is1,4-cyclohexylene and the other group A₂ or A₄ is a divalent cyclicgroup selected from the group consisting of 1,4-phenylene capable ofhaving one or two substituents comprising F, Cl, Br, CH₃, CF₃ or CN,1,4-cyclohexylene, thiophene-2,5-diyl, and indan-2,5-diyl; A₃ is a1,4-phenylene capable of having one or two substituents comprising F,Cl, Br, CH₃, CF₃ or CN; and one of the groups X₁ and X₂ is a single bondand the other group X₁ or X₂ is --OCO--, --OCH₂ -- or --CH₂ CH₂ --. 10.A compound according to claim 7, wherein R₁ in the formula (I) is anyone of the following groups (i*) to (x*): ##STR302## in which a, s andeach are an integer of 1-16; b, g, h and t are each an integer of 0-10;e and f are each an integer of 0-7 with the proviso that a+b≦16 andd+e+f≦15, Z₁ is CH₃, CF₃, F or CN; Y₂ is a single bond, --O--, --COO--or --OCO--; Y₃ is a single bond, --O--, --COO--, --OCO--, --CH₂ O-- or--CH₂ OCO--; and * denotes the location of an optically active center.11. A compound according to claim 7, wherein at least one of A₂ and A₃is a divalent cyclic group selected from the group consisting ofthiophene-2,5-diyl; thiazole-2,5-diyl; thiadiazole-2,5-diyl;benzoxazole-2,5-diyl; benzoxazole-2,6-diyl; benzothiazole-2,5-diyl;benzothiazole-2,6-diyl; quinoxaline-2,6-diyl; quinoline-2,6-diyl;indan-2,5-diyl; 2-alkylindan-2,5-diyl having a linear or branched alkylgroup having 1-18 carbon atoms; indanone-2,6-diyl;2-alkylindanone-2,6-diyl having a linear or branched alkyl group having1-18 carbon atoms; coumaran-2,5-diyl; and 2-alkylcumaran-2,5-diyl havinga linear or branched alkyl group having 1-18 carbon atoms.
 12. A liquidcrystal composition comprising at least two compounds, at least one ofwhich is a mesomorphic compound of the formula (I) according to any oneof claims 1, 2-5, 6-7 or 8-9.
 13. A liquid crystal composition accordingto claim 12, which comprises 1-80 wt. % of a mesomorphic compound of theformula (I).
 14. A liquid crystal composition according to claim 12,which comprises 1-60 wt. % of a mesomorphic compound of the formula (I).15. A liquid crystal composition according to claim 12, which comprises1-40 wt. % of a mesomorphic compound of the formula (I).
 16. A liquidcrystal composition according to claim 12, which has a chiral smecticphase.
 17. A liquid crystal device, comprising a pair of substrates anda liquid crystal composition according to claim 12 disposed between thesubstrates.
 18. A device according to claim 17, which further comprisesan alignment control layer.
 19. A device according to claim 17, whereinthe alignment control layer has been subjected to uniaxial alignmenttreatment.
 20. A device according to claim 17, wherein the liquidcrystal composition is disposed in a thickness suppressing formation ofa helical structure of liquid crystal molecules between the substrates.21. A liquid crystal apparatus comprising a liquid crystal deviceaccording to claim
 17. 22. An apparatus according to claim 21, whereinthe liquid crystal device is used as a display device.
 23. An apparatusaccording to claim 21, which further comprises a drive circuit for theliquid crystal device.
 24. An apparatus according to claim 22, whichfurther comprises a light source.
 25. A display method,comprising:providing a liquid crystal composition according to claim 12;and controlling the alignment direction of liquid crystal molecules toeffect display.
 26. A liquid crystal composition according to claim 12,comprising at least two species of said mesomorphic compound of theformula (I).
 27. A liquid crystal composition according to claim 12,which contains from 3-30 species of mesomorphic compounds according tothe formula (I).